Hairy cell leukemia (HCL) with extensive myelofibrosis responds to thalidomide

We present a 75-year-old man who was admitted to our hospital because of splenomegaly, transfusion-dependent anemia and thrombocytopenia. The diagnosis of idiopathic myelofibrosis was suggested by the bone marrow trephine biopsy, which was hypocellular with myelofibrosis. Thalidomide was started at a daily dose of 100 mg/d and increased to 400 mg/d. Within 12 weeks, thrombocytes increased to 100.000/microl, hemoglobin normalized, lasting for about 11 months. Then, thalidomide had to be discontinued because of mild polyneuropathy. A second bone marrow biopsy showed fibrosis as well as a diffuse infiltration of the bone marrow (80%) by lymphocytes with expression of CD11c, CD19, CD20, CD103. Tartrate resistant acid phosphatase test (TRAP) was also positive. Hairy cell leukemia was diagnosed and he was administered 2-chlorodeoxyadenosine (2-CDA) achieving a complete remission.