Feminizing Adrenocortical Carcinoma in Men: A Rare Cause of Persistent Gynecomastia and a Contemporary Literature Review

Background: Feminizing adrenocortical tumors (FATs) are an exceedingly rare subset of adrenal neoplasms, typically affecting adult men and characterized by an excess of estrogen, suppressed gonadotropins, and gynecomastia. Most FATs are malignant, with a poor prognosis and a high risk of recurrence. Case Presentation: We report the case of a 24-year-old male with bilateral gynecomastia, abdominal mass symptoms, and one year of unexplained infertility. A hormonal evaluation revealed elevated estradiol (90.1 pg/mL) and suppressed ACTH (2.6 pg/mL), with inappropriately normal cortisol levels (12.1 µg/dL). Imaging identified a right adrenal mass. The patient underwent open adrenalectomy, and histopathology confirmed stage II adrenocortical carcinoma (T2NxM0) with autonomous estradiol secretion, negative margins, and a Ki-67 index of 10%. Postoperatively, gonadal function normalized, and infertility resolved at two months. The multidisciplinary tumor board considered but did not initiate adjuvant mitotane, given the completely resected low-stage disease. Conclusions: This case illustrates the rare presentation of feminizing adrenocortical carcinoma with reversible infertility and highlights the importance of early recognition and close surveillance. In addition, our literature review of 12 male cases reported between 2015 and 2025 emphasizes gynecomastia as the hallmark presentation and discusses emerging evidence supporting active surveillance as a potential alternative to adjuvant mitotane in selected low-risk patients.