A 40-year-old woman presents with intermittent positional headaches and episodes of sudden collapse. MRI shows a 1.5 cm well-circumscribed, hyperintense lesion in the third ventricle at the foramen of Monro causing obstructive hydrocephalus. What is the most likely diagnosis?

• A Ependymoma
• B Central neurocytoma
• C Subependymoma
• D Colloid cyst of the third ventricle ✓

Explanation

Colloid cyst of the third ventricle classically presents with intermittent positional headaches due to ball-valve obstruction at the foramen of Monro, sometimes causing sudden drop attacks or hydrocephalus. On MRI, they appear as well-circumscribed, often hyperintense lesions at the foramen of Monro. They are benign and can be resected endoscopically or microsurgically. Central neurocytoma is attached to the septum pellucidum, not at the foramen of Monro.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.