Isolated breast myeloid sarcoma: A diagnostic and therapeutic challenge. A case report and literature review.

IntroductionMyeloid sarcoma is a high-grade hematological malignancy that rarely occurs in the breast as the tumor is generally seen in the ribs, sternum, and orbital bones. We report a case of isolated myeloid sarcoma presenting as a breast mass and reviewed the literature to raise awareness of this disease.Case presentationA 20-year-old girl presented with a painless mass located in the upper outer quadrant of the left breast. The patient underwent a bilateral breast US revealing a central retroareolar large hypoechoic solid mass about 55 × 33 mm. A core needle biopsy was performed leading to the suspicion of non-Hodgkin lymphoma. The patient was planned to start CHOP protocol till the final confirmatory pathologic results. She received 4 cycles with a partial response. A new biopsy from the breast mass and IHC revealed the diagnosis of myeloid sarcoma. Bone marrow examination was normocellular with no abnormal deposits. She received 4 cycles HD Cytarabine with a PET CT revealing a complete response. She is prepared for bone marrow transplantation.ConclusionBeing rare, breast myeloid sarcoma is often misinterpreted as NHL or lobular breast cancer. Oncologists must remain aware of this condition because it frequently co-occurs with or follows AML.