RESUMEN
<p><b>OBJECTIVE</b>To investigate the clinical and pathological features, differential diagnosis of granulocytic sarcoma.</p><p><b>METHODS</b>The clinical manifestations, histopathological features, immunohistochemistry, treatment and prognosis were analyzed retrospectively in 10 cases of granulocytic sarcoma.</p><p><b>RESULTS</b>The age of patients ranged from 10 to 56 years (means = 35.8 years). The male-to-female ratio was 1.5:1. Histologically, the malignant cells of granulocytic sarcoma grew in a diffuse pattern. The cytoplasm was scanty, with eosinophilic fine granularity in some cells. The nuclei were round or focally irregular, and had finely dispersed chromatin. The mitotic figures were visible. Immunohistochemical stains for MPO, CD43, CD117, CD34 and CD99 were positive.</p><p><b>CONCLUSIONS</b>Granulocytic sarcoma can occur in patients of all ages with a male predominance. The diagnosis of granulocytic sarcoma is assisted by the cytochemical stain for naphthol-ASD-chloroacetate esterase and/or immunophenotypic analyses for MPO, CD43, CD117, CD34, CD99. These stains aid in the distinction of granulocytic sarcoma from: lymphoblastic lymphoma, Burkitt lymphoma, diffuse large B-cell lymphoma, small round cell tumours, particularly in children, and blastic plasmacytoid dendritic cell neoplasm.</p>