Phyllodes tumor in ectopic mammary gland tissue: case report and literature review

Ectopic tissue of the mammary gland presents as an embryological alteration, in the involution of the mammary line, with an incidence of 0.2-6% in the population. Axillary polymastia is the most common form of presentation (71%) and can be affected by diseases of the breast tissue: benign and malignant diseases. Phyllodes tumors are unusual fibroepithelial tumors in the mammary gland (1% of neoplasms). Their presentation in ectopic tissue is extremely rare, with only 10 cases having been reported in the literature. We present the case of a patient with unilateral axillary polymastia, in which a borderline phyllodes tumor was developed, showing the process of diagnosis, treatment and follow-up, as well as the review of the literature. (c) 2024 SESPM. Published by Elsevier Espa & ntilde;a, S.L.U. All rights reserved.