Aleukemic myeloid sarcoma of the breast

Myeloid sarcoma is a solid collection of leukemic blast cells outside bone marrow. It is seen infrequently in association with overt Acute Myeloid Leukemia (AML), however, it invariably transforms into this aggressive condition. A 28-year woman presented with a lump in left breast for last 2 years. Morphological and immunophenotypic results of breast mass were consistent with myeloid sarcoma. Bone marrow aspirate and biopsy were normal, however, patient died after one and a half years of diagnosis. Myeloid sarcoma at any extramedullary site heralds development of overt acute myeloid leukemia and should be appropriately managed at the time of diagnosis.