Fibroadenoma in vulval ectopic breast tissue in a patient with PTEN Hamartoma Tumour Syndrome.

PTEN is a tumour suppressor gene involved in regulating cell division. Pathogenic germline variants in PTEN predispose to benign and malignant growths of numerous organs, including of the breast. In the following report, we describe the first documented case of a fibroadenoma developing in ectopic breast tissue of the vulva in a patient with a germline pathogenic variant in PTEN. This highlights the risk of hyperplasia developing in any breast tissue, including rare ectopic sites, particularly in patients with underlying germline variants in cancer susceptibility genes.