[CALLA-positive leukemic multiple myeloma of IgA-kappa type].

A 73-year-old man was admitted into the hospital because of lumbago in October, 1986. Laboratory examination on admission showed anemia, an IgA-kappa Bence Jones proteinemia. The bone marrow picture disclosed a marked involvement by the neoplastic cells, followed by leukemic conversion 2 weeks later. The leukemic cells displayed a lymphoblastoid appearance on light microscopy, but rather compatible with plasma cells on electron microscopy, showing some strands of rough endoplasmic reticulum and a prominent Golgi apparatus in the cytoplasm. The cells expressed a wide spectrum of surface markers, including those of plasma cell (PCA-1, OKT10), B cell (B1, sIg) and CALLA. Reverse hemolytic plaque assay disclosed the immunoglobulin production of monoclonal kappa chain, but a heavy chain production was recognized only in a small proportion of the cells. Under the diagnosis of multiple myeloma, he was treated with vincristine, cyclophosphamide, and prednisolone. But he died of renal failure complicating hypercalcemia after only three months of the admission in accordance with previous reports that CALLA-positive myeloma was associated with poor prognosis. This case may also represent the clinical, morphological and phenotypic diversity in multiple myeloma.