Giant phyllodes tumor of the breast: A case report

Phyllodes tumors of the breast are rare fibroepithelial neoplasms that account for less than 1% of all breast tumors. They tend to affect middle-aged women, who present with a rapidly growing, palpable mass. Here we present a case of a 34-year-old female surrogate mother without any reported personal or family history of breast cancer who presented with a rapidly growing left breast mass, pathologically proven to be a phyllodes tumor. The patient was a G7P7 surrogate mother who received estrogen and progesterone injections for her twin surrogate pregnancy starting 4 months before embryo implantation, after which, she discovered a large palpable mass in the left breast at approximately week 7 gestational age. At the initial presentation, the patient was at week 23 gestational age. She underwent C-section delivery of the twins at this time and obtained further work-up of the mass. She had a core needle biopsy which yielded a benign fibroepithelial tumor. Due to the size of her breast mass and atypical morphology, including extension to the nipple, and skin ulceration, the patient subsequently underwent left mastectomy. At the time of mastectomy, which was 8 months after the initial work-up, the mass had grown to measure approximately 12 × 10 cm on physical examination and took up most of her left breast. It was completely resected and was pathologically determined to be a borderline phyllodes tumor. Only a few cases have been reported about the development of phyllodes tumor during pregnancy in the literature, and we believe this is the first case report of phyllodes tumor related to a surrogate pregnancy. Although the relationship between exogenous hormones and fibroepithelial tumors is not well understood, the case poses the clinical question if screening mammograms should be offered to patients undergoing exogenous hormonal therapy, regardless of age to establish a baseline and monitor for the development (if any) or growth of these tumors.