An ulnar intraneural ganglion arising from the pisotriquetral joint: case report.

Intraneural ganglions of the hand are rare and remain poorly understood. We report a case of an intraneural ganglion arising from the pisotriquetral joint that penetrated the ulnar nerve at Guyon's canal. Although rare, these ganglions should be considered in the differential diagnosis of any neoplasms causing compression neuropathy.