Malignant histiocytosis: a clinicopathologic study of 18 consecutive cases.

The clinical records and histologic material of 18 consecutive patients with malignant histiocytosis were reviewed. The age of the patients ranged from 20 months to 72 years (median 35 years). There were 14 males and 4 females (3.5:1). Lymph node and liver enlargement, fever, and skin nodules were the most common physical findings; and leukocytosis was frequently the most abnormal laboratory test. Seven of 18 patients died, and their survival ranged from 1 to 15 months (median 8 months) after histopathologic diagnosis. The histologic findings on lymph nodes, spleen, liver, bone marrow, and skin were investigated with special reference to both the cellular composition and the pattern of lymph node involvement. Vascular invasion of small perinodal vessels was observed in 4 fatal cases. The absence of capsular invasion and the lack of cohesiveness among atypical proliferating histiocytes of malignant histiocytosis appeared to be inconstant. Sequential lymph node biopsies revealed in later stages the extension of the histiocytic proliferation from the sinuses into the cords and the complete obliteration of the nodal structures. The radiologic investigations yielded numerous pathologic findings that were consistent with the dissemination of the disease. Complete response to initial treatment was achieved in patients that were treated with radiotherapy and/or chemotherapy. Complete response with chemotherapy was achieved only when the treatment included adriamycin. The histologic and clinical features of the present series provide future evidence for the recognition of malignant histiocytosis as a distinct clinical and pathologic entity.