Presentation
A firm, non-tender, scalp lump of chronic duration. Negative history of any previous scalp or cranial trauma.
Patient Data
A focal soft tissue scalp mass, best visualized on the zoomed and modified window. There is no underlying osseous erosion or irregularity. The skull X-ray is otherwise normal.
Ultrasound reveals an intact, avascular, subcutaneous, well- circumscribed, ovoid, encapsulated and heterogenous mass. There is microcalcification. The mass is also extracranial with no bony abnormalities.
CT confirms a benign appearing superficial and extracranial cystic ovoid mass with a thin dense capsule, high vertex. There is no bony erosion or infiltration and additionally no remodeling.
A few scattered punctate dermal calcified nodules consistent with minimal benign primary miliary osteoma cutis.
There are no intracranial abnormalities present.
Case Discussion
Features consistent with an epidermal inclusion cyst on surgical excision.
The DDX included a pilomatricoma (previously called pilomatrixoma) or a trichilemmal cyst especially in view of the typical anatomical location.