Intradiploic epidermoid cyst

There is a well-defined, bilobed lytic lesion of the left parietal bone, with a component in the subcutaneous soft tissues.

Left parietal intradiploic expansile osteolytic lesion, appearing hypodense and showing internal foci of calcification with expansion and erosion of the inner and outer tables of the skull.

A well-circumscribed lobulated mass arising from the left parietal region at the level of the vertex, associated with bony remodeling as well as intra/extracranial extension.

The lesion shows patchy T1 increased signal intensity which could suggest internal hemorrhagic or proteinaceous content. Restricted diffusion is noted on DWI/ADC sequences. Post-contrast imaging did not reveal enhancing areas.