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a rapidly fatal form of lymphoma, characterized by fever, jaundice, pancytopenia, and enlargement of the liver, spleen, and lymph nodes; the affected organs show focal necrosis and hemorrhage, with proliferation of histiocytes and phagocytosis of red blood cells.
malignant histiocytosisA systemic proliferation of large atypical histiocytes that actively phagocytose RBCs, WBCs, platelets and precursors in lymph nodes, splenic red pulp, bone marrow, skin, GI tract, kidneys, adrenal glands and lungs; it is accompanied by bone marrow necrosis, pancytopenia, hepatitis and coagulopathy.
Aggressive, generalised lymphadenopathy, hepatosplenomegaly, pulmonary involvement and pancytopenia; often fatal; fever, weakness, weight loss, diaphoresis, chest and back pain, rash, subcutaneous tumour nodules, pancytopenia, increased bilirubin followed by jaundice; it may cause rapid deterioration.
Male:female ratio, 2–3:1; any age.
While idiopathic, malignant histiocytosis is associated with ALL and AML, post-renal transplantation immunosuppressive therapy and EBV viraemia, as well as lethal midline granuloma.
Virus-associated haemophagocytic syndrome, reactive histiocytosis of T-cell proliferation, AML-FAB M5, hairy cell leukaemia, “histiocytic” and Hodgkin lymphomas, melanoma, anaplastic/large cell carcinoma, infectious mononucleosis, sinus histiocytosis with massive lymphadenopathy, familial haemophagocytic reticulosis, Langerhans’ cell histiocytosis.
Multidrug regimen (e.g., vincristine, cyclophosphamide, doxorubicin, prednisone).
malignant histiocytosisHematology A term that has been used for 3 different conditions
1. Malignant lymphoma. See Lymphoma.
2. 'Regressing atypical histiocytosis' An indolent pre-histiocytic lymphoma accompanied by chromosome defects Clinical Vague heterogenous clinical picture; peak onset in the 3rd decade, commonly with extranodal involvement of the GI tract, skin, BM Prognosis Good.
3. Malignant histiocytosis of Robb-Smith A rapidly fatal disease associated with aggressive proliferation of atypical histiocytes and precursors in lymph nodes, splenic red pulp, BM, skin, GI tract, kidneys, adrenal glands and lungs; although idiopathic, MH is associated with ALL and AML, post-renal transplantation immunosuppressive therapy and EBV viremia, lethal midline granuloma Clinical ♂:♀ ratio, 2-3:1; at any age; fever, weakness, weight loss, diaphoresis, chest and back pain, rash, lymphadenopathy, hepatosplenomegaly, subcutaneous tumor nodules, pancytopenia, ↑ BR followed by jaundice, it may cause rapid deterioration DiffDx AML-FAB M5, hairy cell leukemia, 'histiocytic', and Hodgkin's lymphomas, melanoma, anaplastic or 'large cell' carcinoma, virus-associated hemophagocytic syndrome, infectious mononucleosis, sinus histiocytosis with massive lymphadenopathy, familial hemophagocytic reticulosis, Langerhans' cell histiocytosis; may cause lethal midline granuloma Treatment Multidrug regimen–eg, vincristine, cyclophosphamide, doxorubicin, prednisone. See Histiocytosis.
ma·lig·nant his·ti·o·cy·to·sis(mă-lig'nănt his'tē-ō-sī-tō'sis)
A rapidly fatal form of lymphoma, characterized by fever, jaundice, pancytopenia, and enlargement of the liver, spleen, and lymph nodes; the affected organs show focal necrosis and hemorrhage, with proliferation of histiocytes and phagocytosis of red blood cells.
a condition marked by the abnormal appearance of histiocytes in the blood.
a benign proliferative disease in dogs, particularly Collies and Shetland sheepdogs. there are multiple plaques or nodules in the skin or subcutaneous tissue. The cause is unknown.
a systemic, progressive invasive proliferation of neoplastic histiocytes. Recognized as a familial disorder in Bernese mountain dogs with clinical signs of respiratory disease, involvement of the central nervous system, and anemia.
a proliferative disorder of histiocytes with infiltrates in the skin and lymph nodes. Occurs in young Bernese mountain dogs.
tending to become progressively worse and to result in death; having the properties of anaplasia, invasiveness and metastasis; said of tumors.
see contagious ecthyma.
a form of anthrax in humans.
malignant catarrhal fever (MCF)
an acute highly infectious, fatal herpesvirus disease of cattle, farmed deer and occasionally pigs characterized by an erosive stomatitis and gastroenteritis, erosions on the mucosa of the upper respiratory tract, keratoconjunctivitis, encephalitis, and lymphadenopathy. There are at least two viruses involved. A wildebeest-associated form of the disease is caused by alcephaline herpesvirus 1. It occurs in most African countries in cattle which co-mingle with clinically normal wildebeest and hartebeest. It is epizootic and seasonal. It can also occur in zoological gardens in other countries. Sheep-associated MCF is caused by a poorly characterized virus, presumably ovine herpesvirus 2 (OvHV-2). Cases mostly occur when cattle have had contact with lambing ewes and usually start 1-2 months later. Goats can also act as a source of OvHV-2 infection for cattle. Cases without apparent or recent exposure to sheep do occur but are uncommon. Called also bovine malignant catarrh.
an acute infection of wounds by Clostridium septicum, C. chauvoei, C. perfringens, C. sordellii or C. novyi. The inflammation causes severe swelling and discoloration of skin and exposed tissues. There may be local subcutaneous emphysema and a frothy exudate, depending on the identity of the invading organism. There is a high fever and a profound toxemia; death follows within a few hours if treatment is not provided. Special occurrences are when a large number of animals are affected at one time. These include involvement of the vulva in recently lambed ewes, of shearing or docking wounds, and of the umbilicus or eyes of recently born lambs.
malignant fibrous histiocytoma
a rare aggressive tumor of dogs and cats; composed of densely packed fibroblasts and histiocytes.
malignant head catarrh
see malignant catarrhal fever.
see malignant histiocytosis.
see malignant hyperthermia, porcine stress syndrome.
see malignant carbuncle (above).
theileriasis caused by Theileria hirci.