[Cystic lesions around the joint: ganglion and bursitis]

Cystic lesions such as ganglion and bursitis around the joint are a common problem. Practitioners now encounter such lesions more frequently than previously, thanks to the increased usage of magnetic resonance (MR) imaging in daily practice. The purpose of imaging for periarticular cystic lesions is to confirm the cystic nature of the lesion, to determine the relationship of the cystic mass to the joint and surrounding structures, and to evaluate associated joint disorders. Because of its superior soft-tissue contrast resolution, multiplanar capability, and non-invasiveness, MR imaging is more suitable for diagnosing cystic lesions around the joint than ultrasound, arthrography, or computed tomography. Diagnoses of ganglion and bursitis are readily established when they develop in typical locations and present characteristic imaging features. However, when they contain debris following hemorrhage or infection, or develop in an atypical location, diagnosis may prove difficult. In analyzing a cystic lesion around the joint, it is important to be aware of the possibility of ganglion or bursitis.