Post-traumatic, closed, internal degloving injuries.

One-third of patients present months or years after the initial injury and can mimic a soft tissue tumor, but the location and shape of the lesion, conforming to that of the fascial plane is atypical for tumor.

Site: usually subcutaneous tissues over the greater trochanter. Also described along flank, buttock, lumbar spine, scapula, and knee.

Macroscopic pathology: oval, fusiform, or crescentic, consistent with fluid dissecting along traumatized fascial planes.

MRI findings: hemolymphatic fluid, blood degradation products, fat (viable or necrotic), capsule variably present, varying degrees of enhancement.

The presence of a capsule may be a factor in choosing surgical treatment over conservative management.