Cystic lesion in carpal bone.

Six cases of symptomatic cystic lesions of carpal bones which underwent operative treatment were reviewed. Definite diagnosis, etiology and treatment were also discussed. The lesions occurred in the scaphoid, lunate, capitate and triquetrum, and were multiple lesions in four of the six cases. Juxta-articular bone cyst was diagnosed in three cases: intraosseous cavity surrounded by fibrous membrane containing gelatinous material, and "bone cyst-like pathologic change" in three cases which contained fibrous connective tissue resembled the thick inner wall of juxta-articular bone cyst histologically. They were treated by curettage and cancellous bone grafting; the outcomes were favourable without complication. It is suggested that the minor trauma resulting from the carpal loading serves as a basis for intraosseous lesion, which initiates intramedullary metaplasia followed by fibrous connective tissue proliferation with/without mucin secretion, and forms cystic cavity.