Distinct subtype within the spectrum of hairy cell leukemia.

Most cases of hairy cell leukemia represent malignancies of B cells. However, recent findings suggest that there is a spectrum of functional capacities within the entity hairy cell leukemia. Two patients with hairy cell leukemia, whose malignant cells in the peripheral blood showed both T- and B-cell features, are reported. The malignant cells of the spleens showed only B-cell characteristics. The hairy cells of both patients did not adhere to glass and lacked the la antigen. Both patients showed pronounced polyclonal hypergammaglobulinemia and developed frank leukemic blood pictures after splenectomy. Within the spectrum of hairy cell leukemia, these two cases probably represent a distinct subtype.