Carpal tunnel syndrome caused by a synovial nodule of the flexor digitorum profundus tendon of the index finger

Abstract

It is rare that a non-neoplastic synovial nodular lesion involves a flexor tendon and causes carpal tunnel syndrome. We describe such a case in this report. Case Report A 52-year-old woman initially was seen in our office because of a 2-year history of numbness in the left hand. At rest, she had hypesthesia, dysesthesia, and slight paresthesia in the thumb, index, and middle fingers, and in the radial half of the ring finger. She had no remarkable pain at night. There was no notable difference in sensory symptoms between day and night. She also complained that tingling began in the index and middle fingers with hand activity. Triggering of the wrist and fingers was not noted. She had no contributory medical history. There was no palpable mass. Phalen's test was negative. Manual muscle testing of the abductor pollicis brevis produced normal results. The electrophysiologic study recorded distal motor latency of 4.7 ms and orthodromic sensory conduction velocity of 36 rrds across the carpal tunnel of the affected wrist. The right wrist was normal. Laboratory results were normal.