Gynaecomastia, the benign proliferation of breast glandular tissue in men is typically caused by an absolute or relative imbalance of oestrogen and androgen effects. Not only does gynaecomastia result in local symptoms, it can cause significant psychological burden. In addition to oestrogen and androgen receptors, breast tissue also expresses receptors for luteinising hormone (LH), human chorionic gonadotrophin (hCG), prolactin, progesterone and insulin-like growth factor (IGF). Several aetiologies are known with endocrine tumours, an important cause of gynaecomastia which needs to be considered.

Rehman and colleagues report a 50-year-old man who presented to their clinic with a 3-month history of painful bilateral gynaecomastia. He had a normal testicular examination. Initial biochemistry showed undetectable follicle stimulating hormone and LH with elevated total testosterone and oestradiol. hCG was found to be high and serial testing demonstrated a progressive rise in hCG levels over 4 months. Positron emission tomography 18F-FDG PET/CT whole body imaging revealed a lesion in the anterior mediastinum and a lung deposit.

Following successful biopsy of the mediastinal lesion, the authors undertook histological examination confirming a diagnosis of a primary mediastinal choriocarcinoma, prior to successful combination chemotherapy treatment with surgical resection of both primary and pulmonary metastasis. The patient remains in remission at 3 years and ran the London marathon this year. The authors comment on choriocarcinomas and explanations for their origin. The case highlights the importance of a thorough biochemical assessment in presenting cases of gynaecomastia, in this case caused by suspected hCG-driven aromatisation of testosterone and hCG receptor homology from an endocrine tumour. Furthermore, early diagnosis and management for this highly aggressive tumour is paramount to ensure the best outcome, as achieved in this case.

Read the full article in Endocrinology, Diabetes & Metabolism Case Reports EDM-19-0060