Atypical Chronic Myeloid Leukemia Presenting with Trilineage Dysplasia and IgG (λ) Type Monoclonal Gammopathy

Abstract

A 78-year-old man was diagnosed as leukocytosis in February 1994. Physical examination revealed marked hepatosplenomegaly. A peripheral blood examination disclosed 95,090/μl leukocytes without hiatus leukemicus, 6.5 g/dl Hb, and 15.0×10⁴/μl platelets. The neutrophil alkaline phosphatase score was 27, and serum VB₁₂ was above 1,600 pg/ml. IgG was identified as monoclonal immunoglobulin of type λ. Bone marrow specimens demonotrated marked granulocytic hyperplasia. Neither the Philadelphia chromosome (Ph¹) nor BCR gene rearrangement was detected; hence, the diagnosis of Ph¹ (-) chronic myeloid leukemia (CML) was made. The patient was treated with hydroxyurea and low-dose VP-16 with no improvement, and died of pneumonia and sepsis in June 1995. This case was considered to be consistent with atypical CML (aCML) according to the FAB classification because monocytosis was not observed. It seems likely and interesting that the coexistent monoclonal gammopathy and aCML might have arisen from common abnormal hematopoietic stem cells.