Fragments of a cystic lesion lined by mature, well-differentiated stratified squamous epithelium with a preserved granular layer. The cyst lumen is filled with abundant lamellated, flaky keratinaceous debris. The underlying fibrovascular connective tissue stroma demonstrates the presence of skin adnexal structures. There is no evidence of cytological atypia, invasive growth, or malignancy in the examined fields.
A patient with a one-month history of headaches and gait disturbance underwent a brain MRI and suboccipital craniotomy, which revealed a midline cystic mass in the fourth ventricle suspected to be a dermoid cyst.
Two fragments of open cyst measured collectively 5x3.5x1.5 cm, totally embedded.
Midline cystic mass in the fourth ventricle: