George Haycock, MB, BChir, FRCP, FRCPCH, DCH

• Emeritus Professor of Paediatrics, Guy?, King?, and
• Sr. Thomas?Hospitals School of Medicine, King? College,
• University of London
• Emeritus Consultant Paediatrician and Paediatric
• Nephrologist, Guy? and Sr. Thomas?NHS Foundation Trust,
• London, United Kingdom

A radiograph of the hand shows bulbous swellings that represent nodular masses composed of hyaline cartilage vapor pressure depression definition chemistry order lexapro with a visa, which is sometimes admixed with more primitive myxoid cartilage depression mayo clinic order lexapro master card. A magnetic resonance image of the shoulder of a child shows a prominent lytic lesion of the head of the humerus that involves the epiphysis and extends across the epiphyseal plate bipolar depression 5-htp buy lexapro 20 mg lowest price. The histologic appearance of a chondroblastoma is defined by plump anxiety for dummies quality lexapro 10mg, round cells (chondroblasts) surrounded by a mineralized primitive chondroid matrix depression self test order lexapro on line. In fact, these neoplasms may perforate the cortex, although they remain confined by the periosteum. If neglected, it may (rarely) attain a large size, destroy the epiphyseal area and invade the joint. Curettage is the treatment of choice, although in over 10% of cases, the tumor recurs. One population of mononuclear cells is believed to be of macrophagemonocyte origin and is likely nonneoplastic. Radiologically, the tumor presents as an eccentric, expansile, lytic lesion with no matrix formation, which tends to be surrounded by a thin bony shell. Often, it has a multiloculated or "soap bubble" appearance, representing endosteal resorption of the bone. Radiograph of the proximal tibia shows an eccentric lytic lesion with virtually no new bone formation (arrows). On low-power examination, the tumor often appears as a syncytium of nuclei with poor demarcation of cytoplasmic borders and random distribution of the giant cells. Osteosarcomas are associated with mutations in tumor suppressor genes; almost two thirds show mutations in the retinoblastoma (Rb) gene (see Chapter 5) and many have mutations in the p53 gene. There are also many other chromosomal and molecular abnormalities pertaining to apoptosis, replicative potential, insensitivity to growth inhibitory signals and cell cycle regulation that contribute in some part to the development of the tumor. Virtually all metastases have occurred after an initial surgical intervention and have the benign histology in appearance of the primary tumor. In contrast to patients with lung metastases from other malignant bone tumors, most of these patients enjoy an essentially normal life span, especially if the metastatic deposits are few and can be surgically removed. Thus, historical belief has been that local recurrence of the tumor reflects inadequate resection rather than biological aggressiveness and that distant metastases result from dislodgment of tumor fragments during surgery. Recurrence as pure sarcoma may occur spontaneously or after local radiation therapy. Microfractures and pathologic fractures are frequent, owing to thinning of the cortex. The tumor is treated with thorough curettage and bone grafting, although more aggressive management, including en bloc resection or even amputation, may be necessary. Local recurrence after simple curettage has been reported in one third to one half of cases, and 2%­5% metastasize to the lungs. In older people, they usually occur in the context of Paget disease or radiation exposure. For example, radium watch dial painters, who wetted their brushes by licking them, developed osteosarcoma many years later, owing to radium depositing in their bones. Today, osteosarcoma can develop in adults and children previously subjected to external therapeutic radiation for some other tumor such as lymphoma. Several preexisting benign bone lesions are associated with an increased risk of developing osteosarcoma, including fibrous dysplasia, osteomyelitis and bone infarcts. The proximal humerus is the second most common site; 75% of tumors arise adjacent to the knee or shoulder. Radiologic evidence of bone destruction and bone formation by osteosarcoma is characteristic, the latter representing neoplastic bone. Often, the periosteum produces an incomplete rim of reactive bone adjacent to the site where it is lifted from the cortical surface by the tumor. When this appears on a radiograph as a shell of bone intersecting the cortex at one end and open at the other end, it is referred to as Codman triangle. The gross appearance of osteosarcoma is highly variable, depending on the proportions of bone, cartilage, stroma and blood vessels. The cut surface may show any combination of hemorrhagic, cystic, soft and bony areas. The neoplastic tissue may invade and break through the cortex, spread into the marrow cavity, elevate or perforate the periosteum or grow into the epiphysis and even reach the joint space. Histologic examination reveals malignant polygonal to spindled cells with osteoblastic differentiation, producing woven bone. The malignant cells have large hyperchromatic and pleomorphic nuclei, with a high nucleocytoplasmic ratio. The tumor cells stain prominently for alkaline phosphatase, osteocalcin and osteonectin. The distal femur contains a dense osteoblastic malignant tumor that extends through the cortex into the soft tissue and the epiphysis. A photomicrograph reveals pleomorphic malignant cells, tumor giant cells and mitoses (arrows). Less commonly, the tumor metastasizes to other bones (35%), the pleura (33%) and the heart (20%). Serum alkaline phosphatase is increased in half of patients and may decrease after amputation, only to increase again with recurrence or metastasis. Historically, osteosarcoma was treated exclusively by amputation or disarticulation of the involved limb, but the prognosis for 5-year survival did not exceed 20%. Today, standard therapy with preoperative chemotherapy and limb-sparing surgery gives 5-year disease-free rates from 60% to 80%. Juxtacortical osteosarcoma is a rare variant of osteosarcoma that occurs on the surface of the bone, especially the lower posterior metaphysis of the femur (70% of cases). Unlike classic osteosarcoma, most patients are older than 25 years, and the tumor is more common in women. Juxtacortical osteosarcoma spares the deep cortex and medulla of the bone and grows external to the shaft. Usually, Codman triangle is not evident radiologically, because the periosteum is not elevated. Most juxtacortical osteosarcomas are lowgrade lesions and do not require adjunctive chemotherapy. Other rare variants of osteosarcoma include telangiectatic and small cell osteosarcoma, which are high-grade tumors, and low-grade intramedullary osteosarcoma. Some patients have a history of multiple enchondromas, solitary osteochondroma or hereditary multiple osteochondromas. Chondrosarcoma is the second most common primary malignant bone tumor and is more common in men than in women (2:1). There probably is a different molecular mechanism resulting in tumor development between central chondrosarcoma and secondary peripheral chondrosarcoma (tumors arising in the cartilaginous cap of an osteochondroma; see below). Radiologically, poorly defined borders, a thickened shaft and perforation of the cortex characterize these tumors. There are usually stippled or ring-like radiopacities representing calcification or endochondral ossification in the tumor. Although central chondrosarcoma may penetrate the cortex, extension beyond the periosteum is uncommon. On gross examination, the neoplastic cartilaginous tissue is compressed inside the bone and exhibits areas of necrosis, cystic change and hemorrhage. The cortex of the bone and the intertrabecular spaces of the marrow are infiltrated by the tumor. There is a huge soft tissue mass containing aggregates of ring-shaped and popcorn-like calcifications. A photomicrograph of a chondrosarcoma shows malignant chondrocytes with pronounced atypia. The symptoms of juxtacortical chondrosarcoma are dominated by swelling, with little accompanying pain. Histologically, chondrosarcomas are composed of malignant cartilage cells in various stages of maturity. Occasionally, a well-differentiated chondrosarcoma is difficult to distinguish from a benign enchondroma on cytologic grounds alone. Zones of calcification are often conspicuous and are seen radiographically as splotches or bulky masses. Chondrosarcoma expands by stimulating osteoclastic resorption of bone and often breaks through the cortex. Most chondrosarcomas grow slowly, but hematogenous metastases to the lungs are common in poorly differentiated variants. There is a positive correlation between histologic grade, morphologic features and the degree of karyotypic complexity. Rearrangement of the short arm of chromosome 17 is associated with high-grade chondrosarcoma. Uncommon histopathologic variants of chondrosarcoma include clear cell chondrosarcoma, which occurs almost exclusively in the proximal epiphysis of the femur or humerus and is composed of chondrocytes with abundant clear cytoplasm, areas of woven trabecular Central chondrosarcoma begins with deep pain, which becomes more intense with time. The tumor is only rarely palpable, but in untreated cases, large masses may eventually form. The most frequent location of peripheral chondrosarcoma is the pelvis, followed by the femur, vertebrae, sacrum, humerus and other long bones. Radiologically, characteristic radiopacities, representing calcification or ossification of the neoplastic cartilage, are virtually pathognomonic for the lesion. Macroscopically, peripheral chondrosarcoma tends to be a large bosselated mass that surrounds the base of an osteochondroma and invades and destroys the bone. In the pelvis, the lumbosacral plexus may be compressed, and tumors in the vertebrae may cause paraplegia. It tends to be situated in the metaphysis of long bones, lying on the outer surface of the cortex. Sheets of these cells are interrupted by discrete islands of malignant hyaline cartilage histologically similar to conventional chondrosarcoma. The prognosis for this tumor following complete excision is close to that of a conventional low-grade chondrosarcoma. Dedifferentiated chondrosarcoma is defined as a high-grade nonchondrogenic pleomorphic sarcoma. This tumor usually arises in flat bones of the pelvis or long bones of the extremities and has a dismal prognosis, with less than 10% of patients surviving 5 years. Another variant is known as mesenchymal chondrosarcoma and is histologically characterized by two distinct components. Wide excision is the usual treatment, since response to radiation and chemotherapy is poor. It tends to parallel the distribution of red marrow, so when it arises in the third decade or later, it affects the pelvis and spine. The radiographic findings are variable and depend on the interaction of the tumor with the host bone. There is often a destructive process in which the border between normal bone and the lesion is indistinct. The onion-skin pattern of periosteal bone that is sometimes present on radiologic examination represents circumferential discontinuous layers of periosteal new bone associated with a lytic lesion in the medulla and endosteal surface of the cortex. Some patients present with fever and weakness as well as bone pain, so it is not surprising that their condition may be mistaken for osteomyelitis. It may also diffusely infiltrate the cortical bone or form nodules in which the bone is completely resorbed. It represents only 5% of all bone tumors and is found in children and adolescents, with two thirds of cases occurring in patients younger than 20 years. A segment of the skull from a patient with multiple myeloma reveals numerous punched-out, lytic lesions. Microscopically, the lesions are composed of sheets of plasma cells with atypia, binucleation and discernible nucleoli. Other bones, especially the skull, are common sites for metastases (50%­75% of cases). Metastatic Tumors Are the Most Common Malignant Tumors in Bone In adults, most metastatic lesions to bone are carcinomas, particularly of the prostate, breast, lung, thyroid and kidney. In children, the most common bone metastases are from rhabdomyosarcoma, neuroblastoma, Wilms tumor and clear cell sarcoma of the kidney. It is estimated that skeletal metastases are found in at least 85% of cancer cases that have run their full clinical course. Tumor cells usually arrive in the bone via the bloodstream; in the case of spinal metastases, the vertebral veins often transport them. Multiple Myeloma Produces Lytic Lesions in Bone Malignant plasma cell tumors may be either localized (plasmacytoma) or diffuse (see Chapter 26). Multiple myeloma occurs mostly in older people (average age, 65) and affects men twice as often as women. Because myeloma cells secrete cytokines that recruit osteoclasts, the lesions are unique in that they are almost exclusively lytic. On microscopic examination, sheets of plasma cells show varying degrees of maturity. Amyloid deposits, in both skeletal and extraskeletal sites, are seen in 10% of patients. With newer therapeutic agents, the median survival of patients with multiple myeloma now is about 5 years. Death Joints A joint (or articulation) is a union between two or more bones, whose construction varies with the function of that joint.

Typically characterized by erythema over the bridge of the nose and cheeks depression symptoms test uk 5mg lexapro order mastercard, as well as pustules and papules mood disorder in dsm v discount lexapro 10mg. The late phase of mast cell­mediated reactions is associated with persistent mucosal edema and manifests clinically as nasal obstruction mood disorder online test buy lexapro 5 mg on line. In this condition depression nos discount 10 mg lexapro, the nasal mucosa is thickened by persistent hyperemia mood disorder onset order cheap lexapro line, mucous gland hyperplasia and infiltration with lymphocytes and plasma cells. Inflammatory Polyps Are Nonneoplastic Swellings these polyps arise in the nose and sinuses, mostly from the lateral nasal wall or ethmoid recess. Multiple etiologies are responsible, including allergy, cystic fibrosis, infections, diabetes mellitus and aspirin intolerance. These polyps are lined by respiratory epithelium and have mucous glands within a loose mucoid stroma, containing plasma cells, lymphocytes and eosinophils. Infection followed chronic obstruction of the orifice caused by adenocarcinoma of the nasal mucosa. Sinusitis Is Inflammation of the Mucous Membranes It usually reflects bacterial infections of the paranasal sinuses. If a sinus ostium is blocked, secretions or exudate accumulate behind the obstruction. Maxillary sinusitis may also be caused by odontogenic infections: bacteria from the roots of the first and second molars penetrate the thin bony plate that separates them from the floor of the maxillary sinus. Incomplete resolution of infection or recurrent acute sinusitis may lead to chronic sinusitis, in which the purulent exudate almost always includes anaerobic bacteria. Overlying skin is often markedly edematous, and subcutaneous cellulitis or a subcutaneous abscess also may develop. Osteomyelitis also may spread rapidly between the outer and inner tables of the skull. Septic thrombophlebitis: Sinus infections that penetrate the bone may spread to frontal and diploe venous systems. Resulting septic thrombophlebitis may involve the cavernous venous sinus through the superior ophthalmic veins and is a potentially life-threatening condition. Intracranial infections: Sinusitis may also spread infection to the cranial cavity. Lesions include epidural, subdural and cerebral abscesses and purulent leptomeningitis. Spread may be via lymphatics and veins and need not involve extensive destruction of bone. Syphilis May Destroy the Nasal Bridge Primary chancres in the nose are rare, but mucosal lesions of secondary syphilis are common in the nose and nasopharynx. In tertiary syphilis, inflammation may involve large portions of the nasal mucosa, underlying cartilage and bone. Perichondrial or periosteal gummas may destroy nasal cartilage and bone, causing the nasal bridge to collapse and producing "saddle nose. If infected, a mucocele may cause a sinus to fill with mucopurulent exudate, called a pyocele. Mucoceles occur most often in the anterior compartments ("cells") of frontal and ethmoid sinuses. Mucoceles of anterior ethmoid or frontal sinuses may be large enough to displace the contents of the orbit and occasionally, erode into the central nervous system. Osteomyelitis: Suppurative infection of nasal sinus walls may spread through Volkmann canals to the periosteum, producing periostitis and subperiosteal abscess. If these Leprosy Is Spread through Nasal Secretions Mycobacterium leprae multiplies best at lower temperatures and so prefers cooler body sites, like the nares and anterior nasal mucosa. Tuberculoid and intermediate forms of leprosy account for most cases (see Chapter 9). The skin around the nares and anterior nasal mucosa shows nodules, ulceration or perforations. Nasal involvement is important as leprosy is spread via nasal secretions teeming with bacilli. Fungus balls, or aspergillomas, occur in immunologically normal patients, usually with chronic sinusitis and poor drainage. In this setting, fungi proliferate to form a dense mass of hyphae that causes nasal obstruction. Invasive Fungal Sinusitis Invasive fungal sinusitis usually affects immunocompromised patients. In the rare rhinocerebral aspergillosis, the organisms penetrate venous sinuses and spread to the meninges and brain. Mucormycosis is a potentially life-threatening infection, particularly in diabetic and immunosuppressed patients. It typically involves the nasopharynx but can invade the skin, bone, orbit and brain. The disease is endemic in Sri Lanka and parts of India, and Central and South America. Affected nasal mucosa contains vascular polyploid masses that show marked chronic inflammation and characteristic spherical 50­350-m-diameter sporangia. Rhinoscleroma (Scleroma) Is a Chronic Bacterial Infection Rhinoscleroma is a chronic inflammatory process caused by a gram-negative diplobacillus, Klebsiella rhinoscleromatis. It begins in the nose and usually remains localized there but may extend slowly into the nasopharynx, larynx and trachea. It rarely involves other sites, such as the paranasal sinuses, orbital tissues, skin, lips, oral mucosa, cervical lymph nodes and gastrointestinal tract. Scleroma is endemic in parts of the Mediterranean basin, Asia, Africa and Latin America. Leishmaniasis (Also Known as Kala-Azar) Mucocutaneous leishmaniasis, due to Leishmania braziliensis, commonly affects the nose (see Chapter 9). Initial skin sores heal within a few months, to be followed in some patients by mucocutaneous lesions of the nose or upper lip months or years later. The granulation tissue is very rich in plasma cells, lymphocytes and foamy macrophages. Characteristic large macrophages or Mikulicz cells, contain masses of phagocytosed bacilli. Most Fungal Infections of the Nose and Sinuses Are Opportunistic Pathogenic fungi may involve the nose and paranasal sinuses as part of cutaneous or mucocutaneous infection, particularly in a setting of immunodeficiency (see Chapter 9). Aspergillosis is uncommon, and when it occurs it generally involves a paranasal sinus. Aspergillosis of the sinonasal tract may be noninvasive or invasive, including angioinvasive. A green, nasal mass in a patient with lymphoma demonstrated abundant fruiting bodies. Later, tuberculoid granulomatous responses develop, with few recognizable parasites. Bacterial infection may supervene and lead to soft tissue destruction and collapse of the anterior cartilaginous nasal septum. The sinonasal tract may be the only involved site, or it may be part of systemic disease. Septal perforation and mucosal ulceration may be followed by slowly progressive destruction of the nose and paranasal sinuses, leading to a saddle nose deformity. Constitutional symptoms, such as fever, malaise and weight loss, may accompany resulting "runny nose," sinusitis and nosebleeds. Nasal lesions show ischemic-type necrosis, vasculitis, mixed chronic inflammation, scattered multinucleated giant cells and microabscesses. As the name implies, they show inversion of surface epithelium into underlying stroma. Surgical resection must extend beyond the boundaries of grossly visible lesions, or they may recur. It resembles a wart (verruca vulgaris) and almost always occurs in the nasal vestibule. There are three morphologically distinct lesions collectively called Schneiderian papillomas: inverted, oncocytic (cylindrical or columnar cell) and fungiform (exophytic, septal) papillomas. Squamous cell carcinoma of the maxillary sinus caused an obvious facial deformity, owing to invasion outside the confines of the sinus. The latter is defined by drooping of the mouth to the side of the facial nerve paralysis. Occupational settings reportedly with increased risk for cancer of the nose and sinuses (but for which a specific chemical agent is not identified) are woodworking in the furniture industry, use of cutting oils and leather textile industries. Most other occupational exposures mainly lead to adenocarcinomas and occur mostly in the maxillary and ethmoid sinuses. Because of these occupational risk factors, cancers of the nose and sinuses occur far more often in men and after age 50. These tumors grow relentlessly and invade adjacent structures but typically do not metastasize. The tumor is composed of small round cells with hyperchromatic nuclei and a background eosinophilic stroma representing neurofibrillary matrix. An electron micrograph shows intracytoplasmic, secretory-type, membrane-bound granules with dense cores. Olfactory Neuroblastoma Is of Neural Crest Origin this tumor, also called esthesioneuroblastoma, is uncommon. It has a slight male predominance and occurs in people between 3 years of age and in the ninth decade but a bimodal distribution in the second and sixth decades are most common. It is usually polypoid and highly vascular and shows diverse histologies, depending on the amount of intercellular neurofibrillary material. Tumor cells are slightly larger than lymphocytes, with round nuclei and inconspicuous cytoplasm. They may form pseudorosettes (Homer Wright rosettes) or true neural rosettes (Flexner-Wintersteiner rosettes). The World Health Organization (2005) adopted a four-tiered grading system, based on lobular architecture, mitosis, necrosis, nuclear pleomorphism, fibrillary matrix and rosettes. S-100 protein often surrounds nests or lobules (sustentacular cells), mostly in lower-grade tumors. The cells of olfactory neuroblastomas have intracytoplasmic neurosecretory granules like those of neuroblastomas at other sites. With advancing age, the nasopharynx is replaced by a stratified squamous epithelium over large areas (80%). Waldeyer ring is a circular band of lymphoid tissue at the opening of the oropharynx into the respiratory and digestive tracts. Lymphoid tissue on the superior posterior wall forms the nasopharyngeal tonsils, which, when hyperplastic, are called adenoids. The palatine tonsils are lateral, where the pharynx connects with the oral cavity. They are covered by stratified squamous epithelium, which lines infoldings (tonsillar crypts) into the lymphoid tissue. Crypts normally contain desquamated epithelium, lymphocytes, some neutrophils and saprophytic organisms, such as bacteria, Candida and actinomycetes. Waldeyer ring is well developed in children and its follicles have germinal centers. In fact, the tonsils represent the largest collections of B lymphocytes in a normal child. A malignant cellular infiltrate growing around and into a medium-sized blood vessel with disruption of the external elastic membrane and occlusion of the vessel lumen. Complete removal is critical, and craniofacial resection with chemotherapy and/or radiation therapy provides 85% 5-year survival. Nasal-Type Angiocentric Natural Killer/T-Cell Lymphoma Is Highly Lethal these tumors, once called lethal midline granulomas, midline malignant reticulosis and polymorphic reticulosis, are now recognized as malignant lymphomas. Atrophy of pharyngeal lymphoid tissue is common in chronically immunosuppressed patients. Local radiation therapy also causes marked loss of lymphoid tissue in the Waldeyer ring. Hyperplasia of nasopharyngeal lymphoid tissue follows infections or chronic irritation due to dust, smoke and fumes. Tonsils may enlarge in some primary immunodeficiencies (dysgammaglobulinemia type I or nodular lymphoid hyperplasia), presumably reflecting an adaptive response by the immune system. Similar infiltrates may occur in the upper airways, lungs and alimentary tract, but any organ can be involved. Tumor cells surround small to medium-sized blood vessels (angiocentric); infiltrate through their walls (angioinvasion), often occluding vessel lumens like a thrombus; and cause necrosis in adjacent tissues (ischemic type). Gradually, the nasal mucosa is focally swollen, indurated and eventually ulcerated. Ulcers are covered by a black crust, under which cartilage and bone are eroded, causing defects of the nasal septum, hard palate and nasopharynx, with serious functional consequences. These lymphomas are, at least initially, radiosensitive, and remission with cytotoxic agents has also been reported. Nasopharyngeal inflammation occurs mainly in children but is also common in adolescents and young adults. Viral or bacterial infections may be limited to the palatine tonsils but may also involve nasopharyngeal tonsils or adjacent pharyngeal mucosa, often as part of a general upper respiratory tract infection. These infections are characterized by an exudate or, in the case of diphtheria, a pseudomembrane on the tonsils and pharynx. In pseudomembranous tonsillitis, a necrotic mucosa is covered by a coat of exudate, as in diphtheria or Vincent angina.

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Save for mature cystic teratoma depression symptoms suicidal thoughts 20 mg lexapro buy with mastercard, which affects both sexes equally depression blood test order lexapro online pills, the other tumors occur mostly in males depression test dass order lexapro 5mg otc. Prognosis is like that for comparable gonadal tumors mood disorder vs borderline personality disorder lexapro 5 mg order mastercard, although mediastinal nonseminomatous germ cell tumors are more aggressive depression and anger lexapro 20 mg buy with visa. Thymolipomas are benign, well-circumscribed masses of mature adipose tissue and unremarkable thymic parenchyma. Thymic stromal sarcomas are low-grade malignant mesenchymal tumors with variable morphology, but frequently of a liposarcomatous nature. In these patients, unlike those with myasthenia gravis, the epithelial component of the thymoma is spindle shaped. Other associated diseases include myocarditis, dermatomyositis, rheumatoid arthritis, lupus erythematosus, scleroderma and Sjögren syndrome. Certain malignant tumors may also occur with thymoma, including T-cell leukemia/lymphoma and multiple myeloma. Malignant Thymomas Invade Locally and May Metastasize One fourth of thymomas are not encapsulated and show malignant features. Its morphology is highly variable and it resembles squamous carcinomas, lymphoepithelioma-like carcinomas (identical to those in the oropharynx; see Chapter 29), sarcomatoid variants (carcinosarcoma) and other rare patterns. These variants share a distinct epithelial appearance and a mediastinal tumor that lacks this feature is probably not thymic carcinoma. Paraneoplastic Syndromes Involving the Hematopoietic System Paraneoplastic syndromes are tumor-associated clinical manifestations that occur distant to the tumor and are caused by the secretion of tumor cell products such as hormones, cytokines, growth factors and tumor antigens. Their clinical manifestations are diverse, depending on the organ/system involved, and early recognition of these syndromes may facilitate a timely diagnosis of malignancy. The most effective management of paraneoplastic syndromes in the setting of hematologic malignancies remains the treatment of the underlying malignancy. The following are paraneoplastic syndromes commonly associated with hematologic disorders, grouped by organ system in which the manifestations occur. These resemble comparable tumors elsewhere, clinically and pathologically, and include carcinoids (typical and atypical) and carcinomas (small and large cell). They tend to invade locally and metastasize widely, although they may be cured by local excision if they are well circumscribed. While 1/3 of these patients show Cushing syndrome, carcinoid syndrome is exceedingly rare. Most thymic carcinoids are atypical (intermediate category) with frequent mitoses and/or necrosis. The antibody specificity is against red blood cell antigens, owing to immune dysregulation resulting in the loss of tolerance to self-antigens (in this case, red cell antigens) in the setting of malignancy. If drugs, infections or connective tissue diseases are ruled out, evaluation for a lymphoproliferative disorder needs to be done. Paraneoplastic leukocytosis has been reported in different malignancies of lung, gastrointestinal and genitourinary tract, multiple myeloma, Hodgkin lymphoma and anaplastic large cell lymphoma. Although some studies claimed that the presence of paraneoplastic leukocytosis with malignancies portends a poor prognosis, it is not clear if the association of paraneoplastic leukocytosis and lymphomas has the same impact on prognosis. Eosinophilia without leukocytosis has been described in Hodgkin lymphoma and T-cell lymphoma. Histopathologic evaluation reveals intraepidermal acantholysis, necrotic keratinocytes and vacuolar interface changes. Direct immunofluorescence shows intercellular and basement membrane staining for IgG and complement. Indirect immunofluorescence detects serum antibodies that bind to cell surfaces of stratified squamous epithelia. Sweet syndrome is an acute febrile neutrophilic dermatosis characterized by abrupt onset of papular skin lesions, accompanied by systemic symptoms: fever, arthralgia, malaise, headache and myalgia. Laboratory abnormalities, if present, consist of elevated erythrocyte sedimentation rate and peripheral leukocytosis with neutrophilia. The lesions show dermal edema and dense superficial dermal infiltrate of mature neutrophils, with or without lymphocytes and histiocytes. As a paraneoplastic syndrome preceding or accompanying hematologic malignancies, Sweet syndrome is seen mostly in acute myeloid leukemia and myelodysplastic syndromes. It occurs as well, albeit less commonly, in patients with lymphoid malignancies (hairy cell leukemia, Hodgkin and non-Hodgkin lymphomas). Pyoderma gangrenosum is an ulcerative skin disease, most frequently associated with inflammatory bowel disease and rheumatoid arthritis. When associated with myelodysplastic syndrome, myeloma or leukemia, the presentation can be atypical, with vesiculobullous lesions and atypical distribution. Vasculitides, which manifest as acute-onset rashes, can be paraneoplastic manifestations of malignancies including myeloid leukemias, lymphomas and hairy cell leukemia. In addition, ocular (conjunctivitis), lung (in the form of bronchiolitis obliterans) and nervous system involvement can occur. The disease, immunologic in nature, is initiated by an occult or overt neoplasm, which elicits an immune response in the form of autoantibody production. The autoantibodies are directed against cell surface adhesion molecules (mainly plakin family proteins and desmogleins). Skin biopsy in a patient with Sweet syndrome, which developed clinically 4 months before myelodysplastic syndrome became evident. There is a dense neutrophilic infiltrate in the upper and middermis, sparing the epidermis and without evidence of vasculitis. If antibodies are not found, the differential diagnosis is extensive, since each of the following disorders can be caused by nonneoplastic conditions such as toxins, infections, vitamin deficiencies and metabolic or autoimmune disorders. Paraneoplastic cerebellar degeneration starts with dizziness, vertigo, ataxia and dysarthria. Limbic encephalitis presents with short-term memory loss, seizures, confusion, sleeping problems, psychiatric symptoms, irritability or depression. Although this condition is more common in nonhematopoietic tumors (non­ small cell lung cancer), it may also be seen in lymphomas, both Hodgkin (associated with anti-Tr antibodies) and nonHodgkin (serum anti-Ma2 antibodies). Paraneoplastic encephalomyelitis is an immune-mediated inflammatory disorder that presents as a subacute sensory neuronopathy. Paraneoplastic involvement of the peripheral nervous system, although rare, can occur in lymphomas. Careful differential diagnosis is important since neuropathies due to direct root infiltration by tumor, amyloid deposition or chemotherapy-induced neuropathy are not infrequent. Examples of these include cutaneous leukocytoclastic vasculitis, which is the most common vasculitis associated with hematologic malignancies. Others (polyarteritis nodosa, Churg-Strauss syndrome, microscopic polyangiitis, granulomatous polyangiitis and Henoch-Schönlein purpura) are described in detail in Chapter 17. The mechanisms are either secretion of parathormone-related peptide by tumor cells or excess calcitriol produced by reactive macrophages infiltrating neoplastic lymph nodes. At the ultrastructural level (electron microscopy), glomerular epithelial cells show alterations of their foot processes, which normally regulate protein permeability. The pathophysiology is incompletely understood but involves dysfunctional podocytes due to cytokine production by infiltrated lymphocytes and macrophages. Glomerular lesions are focal (only some glomeruli are affected) and segmental (portions of the glomeruli are affected), and commonly, tubular atrophy and interstitial fibrosis also occur. As with other paraneoplastic disorders, a direct anatomic relationship between the malignant tumor and the sites of manifestation needs to be excluded. Paraneoplastic polyarthritis, presenting as acute or chronic forms affecting both large and small joints, was described in several cases of B-cell lymphoma and acute leukemias of both lymphoid and myeloid lineage. In most cases, treatment of the underlying malignancy is followed by remission of the rheumatologic disorder. They manifest with severe muscle weakness, skin manifestation, respiratory muscle weakness and dysphagia, and their clinical course parallels the course of malignancy. Sjögren syndrome, which clinically presents with keratoconjunctivitis sicca and xerostomia (dryness of eyes and mouth), can be a paraneoplastic manifestation of non-Hodgkin lymphoma or chronic lymphocytic leukemia. According to some studies, generalized pruritus is caused by malignancy in less than 10% of cases. Although the nervous and endocrine systems use some of the same soluble mediators and sometimes overlap functionally, the endocrine system is unique in its ability to communicate at a distance using soluble mediators, hormones. The term hormone (from the Greek, horman, "set in motion") applies to chemicals secreted by "ductless". Diseases of the endocrine system may entail too little or too much hormone secretion. Target tissue insensitivity may simulate the clinical picture of hormone underproduction. It sits at the base of the brain in a bony cavity called the sella turcica, within the sphenoid bone. The anterior lobe, or adenohypophysis, arises from the ectoderm, makes up 80% of the gland and is populated by epithelial cells. The posterior lobe, or neurohypophysis, originates from neuroectoderm as a prolongation of the hypothalamus. Along its migration tract, this craniopharyngeal duct may leave intrasphenoidal squamous epithelial rests that may later give rise to tumors known as craniopharyngiomas. The neurohypophysis (posterior lobe) begins as a downward projection of the brain and remains connected to the Hormone-producing cell Responding cell Synaptic. Biological messages may be transmitted by mechanisms other than the classic endocrine pathway via the circulation. Hypothalamohypophysial tract catecholamines, are produced in multiple sites and may act either locally or through the circulation. Other mediators function only in restricted circulation compartments: hypothalamic hormones only act on the pituitary and reach it via portal tributaries without entering the systemic circulation. Finally, many hormones exert their effects in the very tissues that make them, such as müllerian-inhibiting substance. Flanked on either side by the anterior and posterior lobes is a vestigial intermediate lobe, containing a few cystic cavities lined by cuboidal or columnar epithelium and considered as part of the anterior pituitary in humans. It has a complex portal system that originates in the hypothalamus, and a separate arterial and venous blood supply. The hypophysial portal system transports stimulatory and inhibitory hypothalamic-releasing hormones to the anterior pituitary. Venous drainage from the pituitary follows the cavernous sinus to both inferior petrosal sinuses. Axons and unmyelinated nerve fibers from the hypothalamus proceed along the pituitary stalk to the neurohypophysis and are the nerve supply of the posterior lobe. The cells of the anterior pituitary are arranged in cords or nests in a highly vascular stroma. These cells were classically divided into two groups of equal number: stainable and unstainable cells, based on their hematoxylin and eosin (H&E) staining properties. The cytoplasmic granules of stainable cells appeared acidophilic (eosinophilic) (40%), which contain polypeptide hormones, and basophilic (10%), which contain glycoprotein hormones. Basophilic corticotrophs of the pars intermedia may cluster and spread deep into the posterior lobe, a phenomenon called "basophil invasion. Somatotrophs: these acidophilic cells produce and secrete growth hormone and constitute half of the hormone-producing cells of the adenohypophysis. Both of these hormones are formed in neurons in the hypothalamus and transported along axons to the neurohypophysis. A rich network of capillaries surrounds the axon terminals and facilitates hormone release into the vasculature. The effects of hypopituitarism vary with the extent of the loss, specific hormones involved and age of the patient. In general, symptoms relate to deficient function of the thyroid and adrenal glands and the reproductive system. The tumor itself may be functional, but symptoms of hypopituitarism often result because the tumor compresses adjacent tissue. It is often caused by severe hypotension from postpartum hemorrhage or, rarely, without massive bleeding or after normal delivery. The pituitary is particularly vulnerable during pregnancy, because of reduced blood flow associated with its enlargement at this time. The result of the damage to the gland is permanent underproduction of essential pituitary hormones (hypopituitarism). An immunohistochemical stain (inset) demonstrates cells that synthesize growth hormone (somatotropes). The process can be primary if only the gland is involved or secondary if it is associated with an underlying systemic condition such as fungal or tuberculous infection. Involvement of the hypothalamic­pituitary axis in Langerhans cell histiocytosis (see Chapter 26) causes endocrine abnormalities including diabetes insipidus in 5%­50% of patients and panhypopituitarism in 5%­20%. Panhypopituitarism may occur in hemochromatosis (see Chapter 20), owing to iron deposition in the pituitary. This mutation is also associated with Pickardt syndrome, an uncommon form of tertiary hypothyroidism caused by abnormalities in the portal veins connecting the pituitary with the hypothalamus. Mutations are associated with Rieger syndrome, an autosomal dominant condition with variable phenotypic expression including pituitary abnormalities. Laron syndrome occurs mainly in people of Mediterranean origin, such as Sephardic Jews. Clinical presentations are heterogeneous, and most cases are unique to particular families or geographic areas. Kallmann syndrome is usually diagnosed at puberty because of a delay in the appearance of secondary sex characteristics. Most cases are sporadic, but there are familial forms, some of which are X-linked, while others are autosomal dominant or recessive.

The red blood cells must also be able to withstand hypoxia bipolar depression hotline numbers purchase lexapro 10mg fast delivery, hypoglycemia and acidosis that characterize the stromal cord microenvironment depression symptoms dementia purchase lexapro 20 mg with amex. The spleen normally removes half of aged erythrocytes; the liver anxiety 9 months after baby discount lexapro 10mg buy on line, bone marrow and other organs deal with the rest depression symptoms how long generic lexapro 10 mg without prescription. After phagocytosing and breaking down erythrocytes depression residual symptoms lexapro 10 mg order with visa, macrophages first store the resulting iron as hemosiderin. This pigment then binds to transferrin, leaves the macrophages and travels to the bone marrow to be reused in erythropoiesis. A section of an affected rib shows proliferated Langerhans cells and numerous eosinophils. Electron micrograph showing a Birbeck granule (arrow) in Langerhans histiocytosis. In some cases, these lesions present as a multifocal, typically indolent disorder, localized to one organ system, largely bone. Children ages 2­5 generally present with multiple bony lesions that may be associated with soft tissue masses. The rarest of all forms of these diseases (<10% of cases) is an acute, disseminated variant that usually occurs in infants and children under age 2. Skin lesions, hepatosplenomegaly, lymphadenopathy and bone lesions, along with pancytopenia, are typical. The cells accumulate in an environment with eosinophils, histiocytes and small lymphocytes. Langerhans cells are large (15­25 m), with grooved nuclei, delicate vesicular chromatin and small nucleoli. These cells contain distinctive rod-shaped or tubular cytoplasmic inclusions with dense cores and a double outer sheath, called Birbeck granules. Skin involvement, mainly in the Letterer-Siwe variant, resembles seborrheic or eczematoid dermatitis, and is most prominent on the scalp, face and trunk. Patients show painless localized or generalized lymphadenopathy and hepatosplenomegaly. The classic triad of diabetes insipidus, proptosis and defects in membranous bones occurs in only 15% of cases of Hand-Schüller-Christian disease. Without this function, such as after splenectomy, red blood cell membrane may accumulate, relative to the amount of hemoglobin. One third of the blood platelet pool and a small fraction of granulocytes normally reside, undamaged, in the spleen. Splenectomy, then, is followed only by increases in platelet and granulocyte counts. In hyposplenism, normal splenic functions are impaired by disease or are absent after splenectomy. Nuclear remnants and Howell-Jolly bodies are present in many of circulating erythrocytes. Asplenia, congenital absence of the spleen, occurs once in 40,000 births, and often accompanies other congenital anomalies. Acquired asplenia occurs in young adults with sickle cell anemia, after a period of hypersplenism. In these patients, multiple infarctions eventually lead to splenic atrophy and hyposplenism. Episodic infarction is often painful because of secondary fibrinous perisplenitis. Without the spleen to sequester erythrocytes and remove redundant materials from them, excess membrane and intracellular debris persist, and many red cells assume target shapes and carry nuclear remnants, Howell-Jolly bodies or even intact nuclei. Accessory spleens are common congenital anomalies and occur in 1/6 of pediatric splenectomies. They are usually solitary and involve the splenic hilum, the tail of the pancreas or the gastrosplenic ligament. After splenectomy, accessory spleens may enlarge, but they rarely become large enough to replace the functions of a lost spleen. Other congenital anomalies of the spleen include polysplenia with multiple small splenic masses, fusion, hamartomas and cysts. Thus, splenomegaly is common in many unrelated benign and malignant diseases (Table 26-23). Acute splenitis occurs in many blood-borne infections: the spleen becomes congested, with red and white pulp infiltrated by neutrophils and plasma cells. In acute and chronic parasitemias, the red pulp may be engorged with parasites and their breakdown products. It shows fibrous thickening of the capsule and trabeculae, with slate gray to black coloration of the pulp because of phagocytosed malarial pigment (hematin). In infectious mononucleosis, half of patients have splenomegaly, which may rarely lead to potentially fatal splenic rupture. A polymorphic population of T and B immunoblasts, which may include large multinucleated forms, permeates the red pulp cords and sinuses. Germinal centers are prominent, as in rheumatoid arthritis, and the red pulp has a parallel increase in mononuclear phagocytes, immunoblasts, plasma cells and eosinophils. In systemic lupus erythematosus, fibrinoid necrosis of the capsule and concentric, or "onion skin," thickening of penicilliary arteries and central arterioles of the white pulp occur. Congestive Splenomegaly Chronic passive congestion of the spleen causes splenomegaly and hypersplenism. This occurs most often in patients with portal hypertension due to cirrhosis, thrombosis of the portal or splenic veins or right-sided heart failure. Splenic congestion also complicates hereditary hemolytic anemias and hemoglobinopathies. Common inherited causes of hemolytic anemia include hereditary spherocytosis and elliptocytosis, thalassemia and sickle cells anemia. Erythrocytes in these conditions are inflexible, so they become trapped as they attempt to pass through splenic cords. The cut surface is firm, and the color varies from pink to deep red, depending on the extent of fibrosis. Venous sinuses are distended with red cells and surrounded by hemosiderin-laden macrophages. Later, because of hypoxia and infarcts, splenic parenchyma becomes fibrotic, and the red pulp is hypocellular. Foci of old hemorrhage persist as Gamna-Gandy bodies, fibrotic nodules containing iron and calcium salts encrusted on collagenous and elastic fibers. Infiltrative Splenomegaly the spleen may be enlarged owing to increased cellularity or deposition of extracellular material, as in amyloidosis. Splenic macrophages accumulate in chronic infections, hemolytic anemias and a variety of storage diseases (see Chapter 6). Diverse neoplastic and reactive bone marrow diseases lead to extramedullary hematopoiesis and corresponding increases in spleen size. Malignant cells may infiltrate the spleen in hematologic proliferative disorders, such as leukemias and lymphomas, and in virus-associated hemophagocytic syndrome. Hydatid, or echinococcal, cysts are the most common cysts worldwide, in areas endemic for Echinococcus granulosus (see Chapter 9). Vascular tumors are the most common nonhematopoietic neoplasms that involve the spleen. Various developmental anomalies are associated with immune deficiencies (see Chapter 4) and hematologic disorders. The vascular spaces in hemangiomas contain erythrocytes; in lymphangiomas they have lymph. Splenic hemangiosarcomas are rare, highly malignant neoplasms of vascular endothelial cells that tend to metastasize to the liver via the portal drainage. Despite its large blood supply and filtering function, the spleen is only rarely involved by metastatic solid tumors, and then only in the setting of wildly metastatic cancers. Thymus the thymus elaborates many factors (thymic hormones) that play key roles in maturation of the immune system and development of immune tolerance. On this basis, we discuss certain entities associated with thymus abnormalities in this chapter. Its fibrous capsule extends into the parenchyma, forming septa that delimit lobules. The thymus is largest, relative to total body size and weight at birth, when it averages about 15 g. The former consist of densely packed lymphocytes, which in this location are called thymocytes. Hassall corpuscles are medullary structures that are focally keratinized, concentric aggregates of epithelial cells characteristic of the thymus. It also has a small population of neuroendocrine cells, which may explain how neuroendocrine tumors arise in this organ. There is also a complement of myoid cells, which resemble striated muscle cells but are nevertheless regarded as epithelial cells. Beginning at puberty, the thymus starts to involute and continues to diminish in size into adulthood. Eventually, the thymus is little more than islands of epithelial cells depleted of lymphocytes and aggregates of Hassall corpuscles separated by adipose tissue. It is one of the most common (of 180 at least) genetic syndromes associated with variable clinical manifestations. Patients with DiGeorge syndrome fail to develop their 3rd and 4th branchial pouches, resulting in thymic and parathyroid agenesis or hypoplasia, congenital heart defects, dysmorphic facies and other congenital anomalies. As a result, patients have hypocalcemia and deficient cellular immunity, with a particular susceptibility to Candida infections. Endocrine abnormalities include hypocalcemia, thyroid dysfunction and short stature. In Nezelof syndrome, lymphopenia, hypoplastic lymphoid tissue, abnormal thymus architecture and abnormal T-cell function are the rule. It resembles DiGeorge syndrome, save for the lack of parathyroid and cardiac manifestations. This syndrome entails a hypoplastic thymus, recurrent infections, eczema and thrombocytopenia (see Chapter 4). Patients are highly susceptible to lymphoid malignancies and autoimmune disorders. It results in lymphopenia, granulocytopenia and death, either in utero or in the neonatal period. Swiss-type hypogammaglobulinemia is an autosomal recessive disorder with severe thymic hypoplasia or dysplasia. Infants with this condition have no lymphocytes or Hassall corpuscles in the thymus and die within a few years from infection. Ataxia-telangiectasia (A-T) is an autosomal recessive cerebellar ataxia associated with immunodeficiency, telangiectasia, increased sensitivity to ionizing radiation and frequent occurrence of lymphoma. The tumor in cross-section is whitish and has a bulging surface with areas of hemorrhage. This thymus removed from a patient with myasthenia gravis shows lymphoid follicles with germinal centers. The total weight of the thymus is usually in the normal range, but may be slightly increased. The follicles contain germinal centers, composed largely of B lymphocytes that produce IgM and IgD. Thymic hyperplasia occurs in 2/3 of patients with myasthenia gravis (see Chapter 31). Interestingly, thymic epithelial and myoid cells contain nicotinic acetylcholine receptor protein, which may stimulate the development of antibodies against that receptor. Thymic follicular hyperplasia also occurs in other autoimmune diseases, such as Graves disease, Addison disease, systemic lupus erythematosus, scleroderma and rheumatoid arthritis. Thymomas contain a mixture of neoplastic epithelial cells and nontumorous lymphocytes. The proportions of these elements vary from case to case, and even among different lobules. In cases in which epithelial cells predominate, they may show organoid differentiation, including perivascular spaces with lymphocytes and macrophages, tumor cell rosettes and whorls suggesting abortive Hassall corpuscles. This coincident occurrence of thymomas and myasthenia gravis is more common in men older than age 50. When thymoma is associated with myasthenic symptoms, the epithelial cells are plump, rather than spindly. Thymic hyperplasia is almost always present in the nontumorous thymic tissue, and lymphoid follicles may even be present in the thymoma itself. Benign thymomas are irregularly shaped masses that vary from a few centimeters to 15 cm or more. They are encapsulated, firm and gray to yellow tumors that are divided into lobules by fibrous septa. It is felt that they arise from cells left behind when germ cells migrate during embryogenesis. The histologies of mediastinal germ cell tumors are like those in the gonads (see Chapters 23 and 24). Seminomas, embryonal carcinomas, endodermal sinus tumors, teratocarcinomas, immature teratomas and choriocarcinomas all occur. Mediastinal germ cell tumors may on occasion show somatic-type malignant components of sarcoma, carcinoma or hematologic malignancies.

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