Synovial haemangioma of the knee: an under recognised condition.

BACKGROUND: Synovial haemangioma is a rare type of tumour for which only around 200 cases have been reported worldwide. It usually occurs in the female population during the second decade of life and most commonly affects the knee joint. Patients can complain of pain, recurrent knee swelling and limitation of motion. Since these lesions are uncommon and radilogical findings are nonspecific, physician awareness is low and diagnosis is often delayed, leading in turn to treatment delays and irreversible complications of the affected joint.
MATERIALS AND METHODS: We report four cases of synovial haemangioma of the knee seen over a period of 20 years (1993-2013). Age at presentation ranged from six to 43 years (mean of 22.7 years) with an equal male-to-female ratio. Average duration of symptoms prior to treatment was three years--patients were often misdiagnosed and appropriate treatment was subsequently delayed. Radiographs showed moderate to severe degenerative changes. Magnetic resonance (MR) imaging revealed poorly defined intra-articular contrast-enhancing lesions, all of which were of the localised type. Three patients underwent open synovectomy and en bloc excision of the lesion; the fourth deferred surgery but continues to be monitored. Follow-up ranged from one to 11 years; all four patients are doing well, with no signs of symptom recurrence or progression.
CONCLUSIONS: Synovial haemangioma is a rare but treatable condition. It should remain a differential for any patient with recurrent knee-joint symptoms.