Ganglia of the nerve. Presentation of two unusual cases, a review of the literature, and a discussion of pathogenesis.

Two cases of intraneural ganglia are reported: the first reported involvement of the sciatic nerve and the first reported involvement of the tibial nerve in the tarsal tunnel. Both were successfully treated by excision with sparing the neural elements leading to neurological recovery. A review of the literature fails to reveal any consensus that lesions arise from normal synovial cavities. Incision, evacuation, and complete excision under magnification sparing neural elements gives satisfactory results. Excision of the nerve is not indicated. Pathologic examination suggests that the lesion arises by multicentric metaplasia of connective tissue elements of the nerve rather than by invasion.