[Purely endoscopic supracerebellar infratentorial approach for epidermoid cyst in third ventricle].

Background: The epidermoid cyst as a pineal region tumor is an infrequent pathology and with few descriptions in literature. Its prevalence in the third ventricle is 0,0042% of all intracranial tumors. To achieve a complete exéresis we used an endoscopic supracerebellar-infratentorial approach, surgical technique for pineal region approach.

Objectives: The purpose of this work is to show the surgical technique of this novel approach for the treatment of a very infrequent disease.

Methods: 16 years old male patient with history of diabetes insipidus and chronic headaches (m-RS 1). Brain MRI showed a lesion with hyperintensity in T2WI and hypointensity in T1WI. It presents peripheral enhancement with gadolinium and restricted diffusion pattern in DWI. The pituitary stalk also showed enhancement with contrast. Germ cell tumor was a possible diagnosis but tumor cell markers were negative in CSF samples. We decided to make the purely endoscopic approach to the region to make a biopsy and a possible resection. Intraoperative pathology result informed an epidermoid tumor, so we continued with the complete exeresis of the tumor.

Results: We achieved a complete resection of a third ventricle epidermoid cyst with a purely endoscopic supracerebellar-infratentorial approach and a skull base rigid endoscope in a 16 years old male patient. The patient has recovered without any sequelae, headaches free but persistence of diabetes insipidus (m-RS 1). The purely endoscopic supracerebellar-infratentorial approach is a safe option to the surgical management of third ventricle pathologies, in this case, an epydermoid cyst.