Forgotten injury: a late benign complication of an unremoved shrapnel fragment--case report.

A patient is described with a mortar shell shrapnel fragment in the anterior compartment of the right lower leg that had been in situ for 46 years without causing symptoms, when a large hematoma leading to a "chocolate cyst" developed around it. Initially, the patient was thought to have a malignant tumor. Roentgenograms and CT scans showed shrapnel fragments, and the cyst was removed surgically. A digital subtraction angiogram ruled out any other involvement.