Epidermoid cysts of the spleen are extremely rare, occurring mainly in people under 20 years of age. They are thought to originate from an abnormality in the development of the spleen during the seventh week of embryological life, when the spleen is close to the mesonephric tissues. Cysts present as an asymptomatic abdominal mass or with pain in the left upper quadrant and/or the left shoulder. In the past the recommended treatment has been splenectomy, but with the changing attitudes towards splenic surgery a more conservative approach is now employed. Drainage under radiographic guidance, deroofing with external drainage or simply deroofing with drainage into the peritoneal cavity are now more popular techniques (along with simple cystectomy). Complications are few, although those associated with deroofing and internal drainage are inadequately investigated.
