Synovial hemangioma of the knee joint in a 12-year-old boy: a case report

INTRODUCTION: Synovial hemangioma is a rare condition and is frequently misdiagnosed, leading to a diagnostic delay of many years. CASE PRESENTATION: We present a case of an atypical synovial hemangioma in a 12-year-old Caucasian boy with a diagnostic delay of 3 years. CONCLUSION: It is important to know that synovial hemangioma mostly affects the knee joint, showing recurrent bloody effusions without a history of trauma. If there are no intermittent effusions, the diagnosis will be even more difficult. In cases of nonspecific symptoms and longstanding knee pain the diagnosis of a synovial hemangioma should also be considered in order to avoid diagnostic delay. Magnetic resonance imaging is the main diagnostic tool to evaluate patients with synovial hemangioma, showing characteristic lace-like or linear patterns. Angiography can identify feeder vessels and offers the possibility of embolisation in the same setting. Surgical excision, either done per arthroscopy or per arthrotomy, is recommended as soon as possible to avoid the risk of damage to the cartilage.