Cystic Lesions of the Hand Skeleton.

Cystic bone lesions of the hand encompass a heterogeneous group of entities presenting as mostly well-defined lytic areas on imaging. The most common entities are ganglion cysts and degenerative geodes, typically arising adjacent to joints in adults. Primary masses include simple (unicameral) and aneurysmatic bone cysts. Also, other benign tumors like enchondroma, epidermoid inclusion cyst, giant cell tumor, fibrous dysplasia, tenosynovial giant cell tumor, and brown tumor can appear as expansile lucent lesions. Inflammatory processes such as rheumatoid arthritis or gout often produce focal osteolytic defects resembling cystic cavities. Multimodal imaging is often necessary. Magnetic resonance imaging is useful to detect cystic defects and assess adjacent soft tissues; computed tomography can depict cortical integrity. Radiography is especially helpful to assess aggressiveness of growth and for follow-up. Management depends on symptoms and etiology. Most true cystic lesions are usually treated conservatively. Other symptomatic or aggressive lesions may require curettage, bone grafting, or targeted therapy.