Fine needle aspiration cytology of extramedullary chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) shows extramedullary involvement in 10% of cases. We report the cytologic findings of fine needle aspiration (FNA) of recurrent CML in extramedullary sites in 11 patients with CML. The patients' ages ranged from 24 to 62 years (median, 38 years). There were seven male and four female patients. The aspiration sites were mostly lymph nodes (cervical in 7, retroperitoneal in 2, axillary in 1) and abdominal wall soft tissue (1). The numbers of blasts in the aspirates ranged from 27% to over 90%. Confirmation of the myeloid nature of the blasts was done using naphthol AS-D chloroacetate esterase in one case. Cytologic and flow cytometric immunotyping was done in eight cases. Two cases were based on cytomorphologic features only. Two of the eight immunophenotyped aspirates showed evidence of T-lymphoblastic differentiation. Another showed a mixed myeloid and T-cell phenotype. Blasts were seen in the peripheral blood and bone marrow in 4 of the 11 patients. We thus conclude that extramedullary involvement by CML in our series was associated with younger age, high incidence of cervical lymphadenopathy, increased blasts and frequent lack of bone marrow and peripheral blood involvement. T-cell phenotypes appeared to be higher in our series than reported in the literature. This suggests that there is a need for phenotyping some aspirates of recurrent extramedullary CML, mainly to evaluate the possibility of dedifferentiation and its possible impact on the behavior of the neoplasm.