Blastic variant of hairy-cell leukemia

Three patients with hairy-cell leukemia presented with an unusual combination of clinical and cytologic features. Clinical manifestations included constitutional symptoms, progressive left upper abdomen discomfort, and lymphadenopathy. All three had pancytopenia. Bone marrow aspirate was hypercellular, with extensive replacement by abnormal blastic mononuclear cells with a high nuclear/cytoplasmic ratio. Round, oval, or indented nuclei, with reticular chromatin and prominent nucleoli, and basophilic cytoplasm, with abundant large azurophilic granules, were noted. The bone marrow biopsy specimen showed diffuse involvement in two patients and patchy involvement in one, with absence of fibrosis. The abnormal cells were intensely positive by tartrate-resistant acid phosphatase stain. All of the patients responded well initially to splenectomy. One, who presented with multiple chromosomal abnormalities, had a relatively short survival. The other two are alive. One started therapy with chlorambucil 21 months after operation, and the other presented in a hyperleukocytotic phase five years after operation and responded dramatically to 2'-deoxycoformycin.