Synovial hemangioma--a rare benign synovial tumor. Report of four cases.

We report our clinical experiences in the diagnosis and treatment of four patients with synovial hemangiomata. Synovial hemangiomata are rare causes of recurrent, nonspecific joint complaints and occur most often at the knee joint. Nontraumatic joint swelling combined with recurrent, possibly hemorrhagic joint effusions must be considered signs of a synovial hemangioma. Although no preoperative diagnostic tool enables confirmation of the diagnosis, and MRI seems to be the diagnostic procedure of first choice, it is most important fact for the clinician to be aware of the existence of this disease. Early surgical treatment with excision of the tumor within wide margins of noninvolved normal synovial tissue as partial or total synovectomy is the therapy of choice and avoids degenerative changes as demonstrated with the four cases reported here.