Paradoxical migrating cyst: an unusual presentation of intraventricular neurocysticercosis with a coincidental pituitary adenoma.

Intraventricular neurocysticercosis is an uncommon entity which may become symptomatic due to cerebrospinal fluid flow obstruction. Migration of intraventricular cysts through the ventricular spaces is a rare occurrence. This phenomenon is poorly understood but may be due to pressure changes within the ventricular cavities. We present a patient with intraventricular neurocysticercosis with paradoxical transaqueductal migration of the cyst from the cerebral aqueduct to the fourth ventricle shortly after ventricular drain placement for acute hydrocephalus. The patient also presented with a coincidental sellar and suprasellar mass, later pathologically proven to be a pituitary adenoma. The migration of this cyst resulted in spontaneous relief of obstruction at the cerebral aqueduct, thus restoring normal cerebrospinal fluid pathways and avoiding permanent shunting. We discuss the possible mechanisms and implications of cyst migration, and the diagnostic challenges of concomitant findings of a pituitary mass and neurocysticercosis. Although the presence of a sellar and suprasellar mass in a patient with known neurocysticercosis should raise clinical suspicion for the possibility of sellar neurocysticercosis, pituitary macroadenoma is a more common entity and a more likely etiology for a sellar lesion.