[Diffuse synovial hemangioma of the knee: a case report].

Synovial hemangioma is a rare benign tumor of joint cavities. It may be a cause of pain and recurrent joint swelling in children and young adults. Diffuse synovial hemangioma was diagnosed in a 25-year-old male patient with complaints of right knee pain and swelling of a 10-year history. Direct radiography, venography, magnetic resonance imaging, and diagnostic arthroscopy enabled the diagnosis. Surgical excision was not considered because of diffuse involvement and many pigmented areas in the skin; instead, the patient was monitored conservatively. At the end of a year, the severity of complaints and the size of the lesion did not increase. Since there is a high risk for recurrence following open synovectomy for diffuse synovial hemangiomas, conservative treatment may be an alternative approach in selected cases.