title: Occult Leydig cell tumor in a patient with gynecomastia.
abstract: OBJECTIVE
  To report a case of a clinically occult testicular tumor causing gynecomastia and to alert physicians to the importance of use of testicular ultrasonography in patients with progressive gynecomastia despite normal findings on testicular examination.
  
  
  METHODS
  We present a detailed case, including results of clinical, laboratory, and radiologic assessment, of a man with hyperprolactinemia and gynecomastia.
  
  
  RESULTS
  A 36-year-old man with progressive gynecomastia was referred to our clinic because of an increased serum prolactin level. Subsequent clinical investigation revealed no evidence of hypogonadism and several possible causes of the gynecomastia. Because of the patient's age and progressive symptoms, testicular ultrasonography was performed despite normal findings on testicular examination. This ultrasound study showed a right testicular mass, which proved to be a Leydig cell tumor. The patient was referred for definitive therapy with orchiectomy. Follow-up studies showed resolution of the gynecomastia and substantial decreases in prolactin and estradiol levels.
  
  
  CONCLUSIONS
  Although gynecomastia is a relatively common disorder with a benign cause in most cases, physicians should be aware that normal findings on testicular examination do not completely rule out the possibility of a testicular tumor as the cause. Because of the potentially high morbidity of testicular tumors and their known association with gynecomastia, early performance of testicular ultrasonography in a patient with gynecomastia of unknown cause is advised.
authors.affiliation: Neuroendocrine Unit and Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Anderson
authors.forename: E
authors.initials: E
authors.lastname: Brogi
authors.forename: B M
authors.initials: BM
authors.lastname: Biller
mesh_terms: D000328:Adult; D004958:Estradiol / Q000097:blood; D006177:Gynecomastia / Q000209:etiology*; D018937:Hepatitis C Antibodies / Q000097:blood; D006556:Heroin Dependence; D006801:Humans; D006966:Hyperprolactinemia / Q000209:etiology; D007984:Leydig Cell Tumor / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D009919:Orchiectomy; D012907:Smoking; D013736:Testicular Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D013737:Testis / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography
chemical_list: D018937:Hepatitis C Antibodies; D004958:Estradiol