Dermoid tumor with diastematobulbia

Dermoid tumors are rare congenital lesions and account for 0.2% to 1.8% of all intracranial tumors. Dermoid tumor with diastematobulbia is very rare.

We report a dermoid tumor in an adult female with an unusual location and morphology. The lesion had 2 major components with different material within the cysts. The posterior part of the dermoid had presented on the floor of the fourth ventricle and had split the pons into 2 distinct halves. The anterior part of the lesion was situated in the prepontine cistern and encircling the anterior half of the brainstem. The lesion was radically excised, and the postoperative images showed return of the 2 halves of the pons to appose each other in the midline.

This case report demonstrates the anatomical peculiarities of this extremely unusual presentation of a dermoid cyst with diastematobulbia. Total excision of the lesion through a dorsal approach resulted in a good outcome.