Myeloid metaplasia of the breast. A lesion which clinically mimics carcinoma.

The authors report a case of myeloid metaplasia of the breast presenting as a tumor mass with homolateral axillary lymphadenopathy. The lesion was clinically misinterpreted as a breast cancer and developed in an elderly woman 8 years after the diagnosis of primary myelofibrosis was made. Immunohistochemical and ultrastructural studies confirmed the haematopoietic nature of the proliferating cells. The differential diagnosis from other breast lesions is discussed.