Symptomatic intraspinal synovial cyst in a 66-year-old marathon runner.

A 66-year-old marathon runner developed an intraspinal synovial cyst arising from the L5-S1 zygapophyseal joint, clinically characterized by episodic pain, paresthesia and sense of coldness. Symptoms were predictably and completely relieved by running; Valsalva maneuver elicited the pain, paresthesia and cold sensation. A precisely similar episode occurred 3 years previously on the right side and disappeared spontaneously without recurrence. Routine films and myelogram were not diagnostic; a CAT scan showed the lesion. The cyst was successfully resected; the patient has been asymptomatic for 2 year postoperatively.