Objective: Granulocytic Sarcoma (GS), a rare solid tumor of immature myeloid cells in exrtamedullary sites, usually occurs during the natural course of acute myelogenic leukemia (AML). Rarely is presented without overt hematological disease. The breast is an uncommon site of localization. Method: We report a case of breast GS with aleukemic presentation, condition that is extremely rare and requires a high index of suspicion for diagnosis. A 46 year old woman, presented with a solitary, non-tender, palpable left breast mass. A lumpectomy was done. Results: Histopathology revealed breast parenchyma diffuse infiltration, in a targetoid pattern, by immature small cells intermingled with eosinophils. Lobular carcinoma and lymphoma were considered in differential diagnosis. The myeloid origin of the neoplasm was established by immunohistochemical analysis that revealed LCA, MPO, CD34, HLADR, CD68 (Kp1) positivity. There was no evidence of leukemia in the peripheral blood and bone marrow. The patient was treated as AML with systemic chemotherapy and 5 months after the diagnosis she is without evidence of disease. Conclusion: Breast GS is a challenging situation both for pathologists and hematologists. Available evidence strongly favors the application of systemic chemotherapy despite the appeared localized nature of the disease. Method: Paraffin blocks of tumor tissue of 152 breast cancer cases collected at our Cancer Centre for 3 years. The immunohistochemical study was performed by standard techniques using following antibodies (Dako): ER, PR, HER-2, EGFR, CK5/6, CK17, Ki67. Results: All cases were classified into the 5 subtypes: luminal A (n = 91; 59.8 %); luminal B (n =13; 8.6 %); HER-2-positive (n=19; 12.5 %); basal (n=19; 12.5 %); 5negative (n=10; 6.6 %). Conclusion: Luminal breast cancer phenotype predominates in our collection, predictive/prognostic value of molecular genetic subtypes is planned to be investigated. We recognized statistically significant differences (P<0,001) in five-year survival rates between tumors of luminal (A, B) and basal subtypes.