The cytology of malignant histiocytosis (sinusoidal hematolymphoid malignancy).

Malignant histiocytosis (MH: sinusoidal hematolymphoid malignancy) is a rare lymphoreticular disorder characterized by an aggressive clinical course in younger patients with weight loss, hepatosplenomegaly, generalized lymphadenopathy and pancytopenia. Five cases of MH were identified over a five-year period (1982 to 1987) at Indiana University Medical Center. The patients' ages were 12, 16, 20, 30 and 57 years; all presented with classic clinical symptoms. Four cases were diagnosed by fine needle aspiration biopsy; one case was diagnosed by the examination of ascitic fluid. All patients had confirmatory surgical biopsies. The salient cytologic features of MH included (1) a lack of background lymphoglandular bodies, (2) a population of variably sized dyscohesive cells, (3) a component of large bizarre cells with abundant eccentric, deep-blue cytoplasm on Wright-Giemsa-stained preparations, (4) prominent cytoplasmic vacuolization and (5) inconspicuous erythrophagocytosis occurring in the most benign-appearing histiocytic cells. Ancillary studies on cytologic and histologic material (immunostaining for alpha-1-antichymotrypsin and alpha-1-antitrypsin and staining for nonspecific esterases) confirmed the histiocytic nature of the malignant cells. Recognition of the distinctive morphology of MH and the performance of ancillary studies on cytologic preparations should facilitate the rapid diagnosis and early treatment of this aggressive disease.