An Unusual Case of Gynecomastia Associated With Subclinical Hyperthyroidism

Gynecomastia in males is a medical condition that manifests as the abnormal enlargement of male breast tissue and has a variety of potential causes, which mainly classify as physiologic (infancy, puberty, elderly) and pathologic (hyperthyroidism, medications, cirrhosis, chronic kidney disease (CKD), malignancies). Pathologic causes mainly result from hormonal imbalances. While gynecomastia has been documented in cases of Graves' disease, it is rarely the presenting symptom with very few cases reported in the literature. Here we report an uncommon case of a 65-year-old male with bilateral gynecomastia who presented to his primary care physician (PCP) with concern for breast sensitivity and enlargement. Ultrasound of his breasts showed bilateral findings consistent with gynecomastia. Initial lab demonstrated suppressed thyroid-stimulating hormone (TSH) levels high, normal FT4, elevated estradiol level, elevated sex hormone-binding globulin (SHBG), and elevated total testosterone. The patient was seen by an Endocrinologist six months post-symptom onset and reported that his symptoms had resolved spontaneously.