This patient went on to have a craniotomy and excision of the lesion.
The sections show a cyst, which is lined by keratinising squamous epithelium with focal parakeratosis. The squamous cells show no evidence of dysplasia or malignancy. No adnexal structures are identified. The stroma is fibrous. The features are those of an epidermoid cyst.
FINAL DIAGNOSIS: epidermoid cyst