Carcinoma Mioepitelial Originado en un Adenomioepitelioma: un Reporte de Caso

Myoepithelial carcinoma (MC) is a rare malignant neoplasm originating from myoepithelial cells found in various glands, including the mammary gland. Its clinical presentation is nonspecific, typically appearing as a rapidly growing mass. This case reports an 80-year-old patient with breast pain, a palpable mass, and bloody nipple discharge. A biopsy confirmed a myoepithelial carcinoma arising in an adenomyoepithelioma (AM) with a 3 mm invasive component. A central quadrantectomy was performed, revealing negative margins, and the sentinel lymph node biopsy was also negative. The patient received adjuvant radiotherapy, and due to the tumor’s histological characteristics, no additional systemic therapy was administered. This case highlights the importance of considering AM in the differential diagnosis of breast lesions in postmenopausal women and underscores the role of immunohistochemistry in its diagnosis. The patient remains under semi-annual follow-up with no evidence of recurrence to date.