We report an unusual case of chest wall tumor iu a 27-year-old patient. A c
omplete resection was accomplished, and the patient had an excellent postop
erative course. Histologically, the mass was confirmed to be an ectopic syn
ovial bursa cyst, Although rare, synovial cysts should be considered in any
case of a fluctuating chest wall mass. We also discuss the etiology and di
agnostic approach of cystic masses of the chest wall.