PTH and pachyonychia congenita: There were no significant difference in the male/female ratio, history of PHPT (4.1±4.6 years, ranged from 0.5∼20 years), age at diagnosis of PHPT (49.5±13.7 years), size of tumors (2.97±1.18 cm), and biochemical markers including serum calcium (3.18±0.40 mmol/L), serum PTH (17.3±13.8 folds of upper limit of normal range) of patients with benign parathyroid tumors compared to those with PC.