Myeloid sarcoma of female breast is a rare presentation of acute myeloid leukemia (AML). The tumor mass may precede or occur concurrently with AML, CML, myeloproliferative disorders, and/or myelodysplastic syndromes. Histologically, it looks like a large cell lymphoma and can be misdiagnosed. A case referred as a suspected case of large cell lymphoma. Initial morphological study with conventional H and E staining showed diffuse infiltration of pleomorphic large blast cells with occasional mature cells showing eosinophilic cytoplasmic granules. Immunohistochemical study was done on paraffin material for this suspected case of myeloid sarcoma and tumor cell reaction with myeloperoxidase was positive. The histological diagnosis was finalized as myeloid sarcoma. Initial bone marrow aspiration showed less than 20% myeloid blasts but after three weeks the marrow aspiration showed 30% of myeloid blasts. Flow cytometry was also performed and proved the diagnosis of acute myeloid leukemia. It is concluded that in conditions of an unusual case of pleomorphic large cell lymphoma, myeloid sarcoma may be a possibility.