Lymphoreticular neoplasia in a dog resembling malignant histiocytosis (histiocytic medullary reticulosis) in man.

Malignant histiocytosis was diagnosed in a 4-year-old-dog. Major clinicopathologic findings included multiple cutaneous tumors, peripheral lymphadenopathy, hepatomegaly, lytic bone lesions, anemia, thrombocytopenia, and monoclonal IgA gammopathy. Pathologic findings included multi-systemic infiltration of erythrophagocytic malignant histiocytes. Chemotherapy was unsuccessful.