INTRODUCTION

Soft tissue ganglion cysts, Baker’s cysts, and bursae are relatively common. Other cystic lesions are relatively uncommon with simple or unicameral bone cysts representing only 3% of biopsied primary bone tumors, aneurysmal bone cysts representing 2% of primary bone tumors, and telangiectatic osteosarcomas representing only 2% of all osteosarcomas. The wide spectrum of clinical behavior exhibited by these cystic lesions often requires tissue confirmation of the radiographic diagnosis to insure proper management. As these lesions frequently result in acellular aspirates, definitive diagnosis is often impossible cytologically but the finding of an acellular or hypocellular aspirate may be helpful in confirming the radiographic impression of a benign cystic lesion.

Synovial cysts

Clinical features

Synovial cysts most frequently develop around the knee (Baker’s cysts) but are also known to occur in the shoulder, hip, elbow, hand, and ankle. Most present as a mass near a joint and may or may not be painful. Slow enlargement in size is common and may lead to impairment of joint function.