To the Editor.
—Carpal tunnel syndrome occurs in association with a wide variety of conditions, all of which cause compression of the median nerve in the carpal tunnel.1-6 We report an unusual case of carpal tunnel syndrome caused by calcium apatite deposition in the carpal tunnel, which was caused by secondary hyperparathyroidism.
Report of a Case.
—Carpal tunnel syndrome gradually developed in the right hand of a 49-year-old woman during a two-year period, with severe motor and sensory deficit. Laboratory values were normal except for persistent hypocalcemia, hyperuricemia, and hyperphosphatemia. Roentgenographic examination showed early resorption of the terminal tufts and subperiosteal cortex of the fingers and a large calcific deposit in the carpal tunnel (Figure). Further workup disclosed chronic renal disease and secondary hyperparathyroidism. The patient's condition improved after a surgical incision of the carpal transverse ligament and removal of the calcification, which proved to be calcium hydroxyapatite.