Massive splenomegaly responsive to proguanil and with features of hairy cell leukaemia.

A recent Ethiopian immigrant to Israel presented with pneumococcal sepsis, massive splenomegaly and lymph-adenopathy. Investigations revealed many features of both hairy cell leukaemia (HCL) and hyperreactive malarious splenomegaly (HMS). Proguanil therapy for HMS was followed by rapid, marked decrease in spleen size, disappearance of the tartrate-resistant acid phosphatase-positive cells characteristic of HCL, and increasing eosinophilia, but unchanged lymphadenopathy.