Hairy cell leukemia--an unusual presentation.

Hairy cell leukemia is a chronic lymphoproliferative disorder affecting middle-aged adults, with the median age of 50-55 years. The majority of the patients present with cytopenia. A high count is usually a feature of the hairy cell leukemia variant. We report a case of a 23-year-old male who presented with fever and cough of 15 days duration. His peripheral blood count was 63 x 10(9)/l. His peripheral blood and bone marrow smear showed hairy cells which were positive for tartarate-resistant acid phosphatase stain. Surface markers and electron microscopic study on peripheral blood ruled out hairy cell leukemia variant as a differential diagnosis.