We clinicopathologically analyzed 20 cases of soft tissue hemangioma, and found Magnetic Resonance Imaging to be useful for diagnosing painful lesions. Sixteen of 20 patients complained of pain, increasing after exercise. Difficulty of diagnosing hemangioma depends on disappearance of symptoms and the tumor itself when stopping exercise or resting. A particular hemangioma variant mainly occurring in the synovial tissue of the knee (synovial hemangioma), often causes severe pain and limitation in knee motion mimicking meniscal disorders, making it important to consider the possibility of hemangioma. Angiograms are useful for diagnosing synovial hemangiomas. Other diagnostic modalities, such as CT or MRI are of little help in the clinical diagnosis of this variant. Although MR images show discrete characteristic features of most hemangiomas, CT and MRI showed the synovial variant to be no more than non specific synovitis. Surgical extirpation is a treatment of choice, however, it is not always necessary to resect the lesion completely because of its unclear boundary.
