The difficult exploration for hyperparathyroidism: the missing fourth gland.
D000368:Aged; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000473:pathology / Q000601:surgery