CHRONIC NEUTROPHILIC LEUKEMIA ASSOCIATED WITH MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE

A 30-year-old man with chronic neutrophilic leukemia (CNL) in associat ion with monoclonal gammopathy is presented. Physical examination on a dmission revealed moderate hepatosplenomegaly. Initial blood count sho wed neutrophilic leukocytosis (42.2 x 10(9)/l with 90% mature neutroph ils). Leukocyte alkaline phosphatase (LAP) score was elevated. Bone ma rrow aspiration showed myeloid hyperplasia without dysplastic features . Karyotypic and molecular analyses of bone marrow cells showed the ab sence of Philadelphia (Ph(1)) chromosome and bcr gene rearrangement. B ecause there was no underlying infection or neoplasm, he was diagnosed as having CNL associated with IgG kappa-type monoclonal gammopathy (I gG, 1,269 mg/dl). In addition to its association with monoclonal gammo pathy of undetermined significance (MGUS), the present case was also c haracterized by spontaneous remission of CNL during the 12-year follow -up, accompanied by a gradual increase in serum IgG levels up to 3,000 mg/dl. As far as we know, there have been 19 cases of CNL associated with monoclonal gammopathy in the literature. The median survival of t hese cases was 5 years. Although there have been only 6 cases of CNL a ssociated with MGUS, survival of these cases was particularly favorabl e. Taken together with the observation that leukocytosis and hepatospl enomegaly in the present case subsided without specific treatment, we speculate that myeloid proliferation in the present case may have been a leukemoid reaction to underlying monoclonal gammopathy.