Baker's cyst is a benign lesion that results from degenerative or inflammatory diseases of the knee joint. When Baker's cyst ruptures, it may simulate deep vein thrombosis known as Pseudothrombophlebitis syndrome with calf pain, swelling and redness. Pseudothrombophlebitis syndrome without thrombus in popliteal veins has distinct treatment choice than deep vein thrombus.
In this report, we presented a 47 year-old male rheumatoid arthritis patient with complaints of redness, pain and swelling on his right calf. Pseudothrombophlebitis syndrome was diagnosed due to ruptured Baker's cyst.
We used musculoskeletal ultrasound for both differential diagnosis and treatment of pseudothrombophlebitis syndrome. Ultrasonography revealed massive fluid collection within muscle layers. 280 cc inflammatory fluid was aspirated simultaneously. We also emphasized the importance of ultrasonography in diagnosis and treatment of Pseudothrombophlebitis syndrome with this report.