Chronic myelomonocytic leukemia in a 15-year-old boy

A 15-year-old boy with lymphadenopathy and marked leukocytosis was evaluated. At 2 years old, he was diagnosed to have malignant testicular carcinoma for which radiotherapy and cytotoxic drugs were administered. On admission, the peripheral blood showed an increase of all stages of the granulocytic cell line and atypical monocytoid cells. Cervical lymph node biopsy showed infiltration by immature granulocytic cells. Eleven percent of the peripheral leukocytes was positive for combined staining by alpha-naphthyl butyrate esterase and naphthol-ASD-chloroacetate esterase activity. The leukocyte alkaline phosphatase score was low. Serum and urinary lysozyme levels were markedly elevated. Philadelphia chromosome was not detected. Although chronic myelomonocytic leukemia (CMML) has been described in elderly patients, the findings in this pediatric patient were most compatible with a diagnosis of CMML.