Dysplastic megakaryocytes and eosinophilic precursors in the diagnosis of myeloid sarcoma on lymph node fine-needle aspiration cytology: a case series.

Objective: To analyze the cases diagnosed as myeloid sarcoma on fine-needle aspiration cytology (FNAC) of lymph nodes.

Study Design: Ten cases of lymph node aspirate diagnosed as myeloid sarcoma were analyzed. FNAC was performed as a routine outpatient procedure in all cases. Correlation with peripheral smear, bone marrow examination, flow cytometry and cytogenetics was done wherever possible.

Results: Diagnosis of a hematologic malignancy, before fine-needle aspiration, was available in only 2 cases. All 10 cases showed eosinophilic precursors while five aspirates showed megakaryocytes with dysplastic forms. Of the 10 cases, 3 were diagnosed as acute myeloid leukemia, 3 as chronic myeloid leukemia, 1 case as juvenile myelomonocytic leukemia, 1 case proved to be precursor T acute lymphoblastic leukemia/lymphoma and 2 patients did not show blasts on peripheral blood smear but showed blasts, dysplastic megakaryocytes and eosinophilic precursors in the aspirate.

Conclusion: Thorough workup to search for an underlying hematological malignancy should be done whenever dysplastic megakaryocytes and/or eosinophilic precursors are seen in lymph node aspirate.