gms | German Medical Science

Objectives: SC, a cartilaginous lesion arising from synovial connective tissue, may occur intraarticularly or extraarticularly. SC has been found to occur rarely in an extraarticular location and has no predilection for gender or age. Extraarticular SC tends to affect the hands, feet and wrists most frequently, although it does occur in larger joints such as the knee.

Here, we present a case of extraarticular SC in prepatellar bursa.

Methods: A 48-year-old woman was admitted with painless, bulky soft tissue mass over her patella, which had been slowly growing for 2 years. She was denied any present or past medical history of trauma or rheumatic disease. On physical examination the mass was palpable and it was located on the prepatellar origin of the left knee. The mass was moveable and there was no tenderness with palpation. And also MRI showed multiple round bodies in the prepatellar bursa centrally isointense with medulla and peripherally hipointens on all pulse sequences suggestive of calsification or ossification.

Results and Conclusion: SC is an uncommon tumor-like lesion of multiple cartilaginous nodules, which may occur intraarticularly or, much more rarely, extraarticularly. The pathogenesis of the SC is not known, but it is believed that they form from articular synovial membrane in intraarticular SC, or from bursa or tendon sheath synovium in extraarticular SC. SC is generally regarded as a benign condition, but it is occasionally a localy agressive disease. The risk of developing malignancy from SC has been reported to be 5%. Extraarticular SC tends to affect the hands, feet and wrists most frequently, although it does occur in larger joints such as the knee. Additional locations include the subacromial bursae, temporomandibular joint and sternoclavicular joint. Among these cases, extraarticular SC of the prepatellar bursa has been reported once previously, and this was the second case in the literature. Imaging studies are helpful in diagnosing SC. Radiography, computed tomography, MRI and ultrasounography can be used for the diognosis. But most diognosis currently made by MRI. MRI is considered a better tool for diagnosis because MRI can demostrate uncalcified nodules and demostrate soft tissue involment, found in earlier phases of SC.

In conclusion, extraarticular SC is a benign lesion of multiple nodules of chondrocytes. Most cases occur in intraarticular location but some cases as this case, are extraarticularly in prepatellar bursa. The pathogenesis remains unclear. It may cause pain, swelling and lack of movement due to mass effect. Treatment is to remove the lesion and associated synovial tissue. But if the patient denied surgery you must monitore the patient closely because of the malignancy risk.