Malignant Phyllodes Tumor in Ectopic Breast Tissue: A Case Report with a Literature Review

Supernumerary breasts come from ectopic breast tissue which regression was incomplete. Typically, it is a single supernumerary gland, located in the axilla. Ectopic breast tissue is subject to the same pathologic events that occur in normally positioned breasts. Excision may be required for diagnosis, treatment of symptoms or cosmesis. We report a case report of a female patient aged 22 years, without medical history. She consulted for a left axillary swelling. Breast ultrasound showed: Voluminous mass of axillary tail with polylobed contours, Aspect evoking a phyllodes tumor. The patient had a wide excision. Anapath review concluded: Malignant phyllodes tumor in ectopic breast tissue and absence of residual tumor. Abdominal ultrasound and chest x-ray were normal. Adjuvant systemic treatment and radiotherapy were not delivered. Our patient is regularly followed: She doesn’t develop distant metastases or loco-regional relapse. Axillary ectopic breast tissue may provide a diagnostic challenge, as other benign and malignant lesions occur in this area. Malignant Phyllodes tumor in ectopic breast tissue is an extremely rare occurrence. Wide breast surgery is the mainstay of the treatment of non-metastatic malignant phyllodes tumors of the breast.