18F-FDG PET/CT for staging and detection of extramedullary organ involvement in chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is a rare hematologic malignancy characterized by the accumulation of monocytes in the blood and bone marrow, dysplastic hematopoiesis, and potential leukemic involvement of organs. We report a case of leukemic involvement of cervical lymph nodes detected by 18F-FDG PET/CT. A 53-year-old woman with CMML and newly diagnosed cervical lymphadenopathy underwent whole-body PET/CT for evaluation of extramedullary disease. PET demonstrated marked tracer uptake in cervical lymph nodes. Histopathological evaluation revealed leukemic involvement. 18F-FDG PET/CT is a valuable tool enabling sensitive staging of CMML, particularly in case of extramedullary organ involvement.