Abstract
Myeloid sarcoma, a mass-forming neoplasm composed of myeloid blasts, rarely arises from the breast. It can occur in a patient with concurrent acute myeloid leukemia (AML) or as a relapse of AML. A PET/CT scan of a 26-year-old woman who had been diagnosed as having AML at 21 years of age showed abnormal uptake in both breasts. The patient had experienced several relapses and remissions of AML despite having received umbilical cord blood transplantation, bone marrow transplantation and chemotherapy. She had also been diagnosed with subcutaneous myeloid sarcoma of the head. Ultrasonography showed that the masses in both her breasts were hypoechoic with indistinct margins. A diagnosis of myeloid sarcoma of both breasts was made following a core needle biopsy. The patient received radiotherapy for both breasts, after which PET/CT revealed disappearance of the abnormal uptake in both breasts. Because the clinical and radiological features of myeloid sarcoma of the breast are non-specific, a biopsy is necessary for the diagnosis.
