List five causes of gynecomastia and how you would investigate for them.
| Diagnosis | Investigation |
| Ideopathic, obesity, adolescent | Diagnosis of exclusion |
| Primary hypogonadism | Low testosterone High LH, FSH XYY karyotype |
| Liver cirrhosis | AST ALP Bilirubin Albumin PT |
| Testicular germ cell cancer | b-HCG |
| Drugs: spironolactone, digitalis, cimetidine | History |
| Hyperthyroidism | sTSH Free T4 Free T3 |
| Rare: adrenal estrogen-producing tumour | Estradiol level |
Other rare causes:
- Androgen insensitivity syndrome (partial)
- Ectopic HCG
- Excess aromatization
- True hermaphrodite
