Hairy Cell Leukemia with Cytoplasmic IgM, κ-Type

Abstract

The 79-year-old female patient with a huge spleen, pancytopenia and 10% abnormal cells in the peripheral blood was admitted to our hospital.
The abnormal cells showed hairy appearance under phase microscopy and were peroxidase (-), Naphthol AS-D chloroacetate esterase (-), α-naphthyl butyrate esterase (-), Acid phosphatase (+) and Tartrate-resistant acid phosphatase (-). Surface phenotype analysis of the abnormal cells by ABC immunoperoxidase method showed I2 (+), B1 (+), B4 (+) and MY4 (+). Cytoplasmic immunoglobulins (IgM, κ) were detected in these cells.
Cases of hairy cell leukemia with pancytopenia are rare in Japan. Clinical features of our case were compared with the cases in Japan and in western countries. The nature of hairy cells were also discussed.