Calf pain and swelling: Baker's cyst mimicking deep vein thrombosis.

Venography is often requested to confirm the clinical suspicion of deep vein thrombosis (DVT) in patients with calf pain or swelling. Often, no clots could be demonstrated and the patients are discharged without a confirmed diagnosis. It is now being increasingly recognised that a Baker's (popliteal) cyst, ruptured or otherwise, may simulate deep vein thrombosis. Seven patients with a clinical suspicion of DVT were referred for venography but were found to have no thrombi within the deep veins of the calf. These patients were noted to have knee joint abnormalities. Baker's cysts were confirmed on subsequent knee arthrograms, ultrasonography or magnetic resonance imaging (MRI). It is emphasised here that a failure to demonstrate DVT in a patient with signs and symptoms, of DVT should prompt a search for Baker's cyst. The pathological anatomy of Baker's cyst is briefly reviewed with the aid of magnetic resonance images.