OBJECTIVETo study the clinicopathologic features of granulocytic sarcoma.

METHODSThe clinical and pathologic findings of 38 cases of granulocytic sarcoma were retrospectively analyzed. Immunohistochemical study was performed and the literature was reviewed.

RESULTSThe age of patients ranged from 2 to 77 years (mean = 43.3 years). The male-to-female ratio was 1.5:1. Major clinical presentations included superficial lymph node enlargement and painful soft tissue mass. Follow-up data were available in 18 patients; and 14 of them died of tumor-related diseases. The average duration of survival of the patients was 16.9 months. Histologically, the tumor cells were relatively uniform in appearance and small to medium in size. The cytoplasm was scanty and pale in color. The nuclei were round or focally irregular, with fine chromatin and inconspicuous nucleoli. Mitosis figures were readily identified. Scattered immature eosinophilic myelocytes were seen. Immunohistochemical study showed that the tumor cells in all cases expressed MPO and CD43. Most cases were also positive for CD68, lysozyme, CD99 and TdT. The staining for CD3, CD20, CD79a, pan-cytokeratin and PLAP were negative.

CONCLUSIONSGranulocytic sarcoma is a known histologic mimicker of non-Hodgkin lymphoma, Ewing sarcoma/PNET and embryonal rhabdomyosarcoma. Detailed morphologic examination, when coupled with immunohistochemical study, is useful in arriving at a correct diagnosis.