The Third Eye Sees Double: Cohort Study of Clinical Presentation, Histology, Surgical Approaches, and Ophthalmic Outcomes in Pineal Region Germ Cell Tumors.

BACKGROUND Intracranial germ cell tumors (GCTs) predominantly occur in the adolescent and young adult population and are most frequently located at the pineal gland. Tumor masses in the pineal region may cause ophthalmic symptoms due to compression to the midbrain, frequently presenting with Parinaud syndrome and hydrocephalus due to aqueductal compression. METHODS We conducted a single-institution cohort study of primary, pineal region GCTs to characterize the clinical presentation, as well as associated ophthalmic and hydrocephalus outcomes. RESULTS Fifty-six primary pineal GCTs were identified. Among the 40 isolated pineal region GCTs, 15 were germinomas while 25 were nongerminomatous GCTs. Among 43 cases of hydrocephalus, endoscopic third ventriculostomy was the primary treatment in 27 cases, which was successful in 23 but failed and required additional treatment for the rest. Pineal tumor mass was significantly larger in cases with hydrocephalus compared with those without, and the 20-mm diameter of the tumor was the crucial point for obstructive hydrocephalus. Ophthalmic symptoms were commonly observed at presentation, which included diplopia (74.3%), upward-gaze palsy (69.7%), and Argyll Robertson pupil (40%). These symptoms tended to remain, and the existence of these symptoms at presentation predicted the remaining symptoms in the follow-up. CONCLUSIONS Intracranial GCTs presenting with ophthalmic abnormalities appear to be at increased risk of residual posttreatment symptoms, while second-look surgery presents a significant risk factor for the development of new deficits. Hydrocephalus often accompanies pineal region GCTs, and in most cases both cerebrospinal fluid diversion and tissue diagnosis can be successfully achieved via endoscopic third ventriculostomy.