Breast cancer is infrequently associated with pregnancy. However, such cases often pose diagnostic and treatment problems. The infarction of breast lesions is likewise uncommon, and generally hinders intraoperative morphologic diagnosis. A 33-year-old woman in the 37th week of pregnancy presented with a breast tumoration of progressively increasing size and associating mastalgia. Following fine-needle aspiration and trut-cut biopsy with posterior amplified tumorectomy and axillary dissection, a ductal neoplasm was identified with an infarction affecting 90% of the tumoral surface. The where no axillary adenopathies, and the patient was estrogen receptor-negative. An analysis is made of this rare association of pregnancy and infarcted breast cancer, with an evaluation of the role of fine-needle aspiration and/or gestation may play in the occurrence of tumor infarction.