Unilateral Hydrocephalus Due to Lateral Ventricle Colloid Cyst Treated by Neuroendoscopic Approach.

Colloid cysts (CCs) are rare brain tumors that cause nonspecific neurological signs associated with acute or chronic increased intracranial pressure. They are usually located in the third ventricle and rarely in the lateral ventricle. This is a report of an unusual case of CC located in the lateral ventricle. A 36-year-old male patient presented a story of progressive holocranial headache that would get worse with head mobilization and cough. Radiological analysis demonstrated enlargement of the right lateral ventricle due to a cyst blocking the right foramen of Monro. The patient underwent endoscopic neurosurgery and the cyst was totally resected. Histological evaluation diagnosed a CC. Postoperative images showed no cyst remaining and normalized ventricular size. The patient evolved with total improvement of the symptoms. Literature review shows that it is a very uncommon entity. Lateral ventricle CCs as a cause for unilateral hydrocephalus is a very rare entity. Neuroendoscopic approach is a first-line treatment option for this condition.