The present case describes a two-step endoscopic management of hydrocephalus and diagnosis of a single pineal region metastasis arising from a gastric adenocarcinoma. A 62-year-old man presenting with signs of subacute obstructive hydrocephalus from a pineal region mass had at first been treated with an endoscopic third ventriculostomy. As cerebrospinal fluid tumor markers (alpha-fetoprotein, beta-human chorionic gonadotropin) were negative, an endoscopic biopsy of the pineal region tumor was performed through a more anterior frontal burr hole. Pathology showed an adenocarcinoma and primary tumor work-up revealed an unsuspected gastric tumor, the pathology of which matched with the intracranial metastasis. The present report emphasizes the role of neuroendoscopy in pineal region tumors and reports a rare case of a solitary gastric adenocarcinoma metastasis in this location.