Aneurysmal bone cyst involving the lunate.

Aneurysmal bone cysts are rare lesions which even more rarely involve the bones of the hand. We report a case of a cyst involving the lunate which was initially mistaken for interosseous ganglion. Due to delay in diagnosis, marked destruction of the lunate occurred, necessitating excision and scapho-capitate arthrodesis. Although rare, aneurysmal bone cysts should be included in the differential diagnosis and ruled out prior to embarking on a course of treatment.