Huge colloid cyst: case report and review of unusual forms

The authors report a case of a huge colloid cyst of the septum pellucidum with acute worsening. A 42-year-old man was admitted for unexplained lethargy. A brain CT scan disclosed a huge intra-ventricular lesion. He experienced a sudden deterioration with coma, and was managed with bilateral ventricular external shunting. Total removal was performed a few days later using a right frontal trans-ventricular approach. The discussion focuses on colloid cyst potential to mimic other intracranial lesions, rendering accurate diagnosis difficult and leading to possibly inappropriate management in similar cases.