Cavernous malformations are vascular lesions that occur in all parts of the central nervous system but most commonly in the cerebral hemispheres; unusually they may be found along the midline (basal ganglia, pineal region or brain stem), into the ventricle possibly encroaching upon the fourth and third ventricle. We report a case of midline cavernomas of the IV ventricle, that grew to large size in-time, demonstrating the capacity for rapid expansion.