In the intraventricular type, the cysticercus cyst may be found anywhere in the ventricles, commonly in the midline leading to obstructive hydrocephalus, either acute or chronic (Figs. 7.38-7.43). The wall of the cyst may enhance, secondary to ependymal reaction (Fig. 7.40), and the scolex can be identified at times (Fig. 7.41). The intraventricular lesions may be isodense or isointense with CSF and there may be focal deformity of the affected ventricle (Fig. 7.42). Occasionally, when there is clinical suspicion of ventricular cysticercosis and with no obvious CT and MRI findings of its presence, other studies such as CT ventriculography may be useful to confirm the diagnosis (Fig. 7.43).

Fig. 7.38. Intraventricular cysticercosis. A large cysticercus occupies the fourth ventricle causing obstructive hydrocephalus. CT axial, multiple sections. (Courtesy of Dr. Enrique Palacios, Berwyn).

Fig. 7.39. Intraventricular and parenchymal cysticercosis. Pathological specimen, coronal section. Lesions are seen in the right temporal area, basal ganglia, and third ventricle (arrow). (Courtesy of Dr. Enrique Palacios, Berwyn).

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Fig. 7.40. Small cysticercus cyst in the roof of the third ventricle. (A) Axial CT, postcontrast study, showing ring enhancement of the lesion (arrow). (B) Sagittal MRI, T1-weighted image, confirms the location of the cyst (arrow). (Courtesy of Dr. Enrique Palacios, Berwyn).

Fig. 7.41. Intraventricular cysticercosis. Small cyst in the fourth ventricle producing hydrocephalus. MRI sagittal plane, T1-weighted image. Note scolex in the inferior portion of the cyst (arrow). (Courtesy of Dr. Francisco Garcia).

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Fig. 7.42 A,B. Large cysticercus cyst in the trigone of the right lateral ventricle identified on MRI. (A) Sagittal T1-weighted and (B) axial T1-weighted images, postcontrast. There is significant compression of the quadrigeminal plate and posterior third ventricle. (Courtesy of Dr. Enrique Palacios, Berwyn).

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Fig. 7.43 A, B. Intraventricular cysticercus cyst within the left lateral ventricle with ipsilateral dilatation from obstruction of the foramen of Monro. (A) Axial CT. (B) CT ventriculogram: following opacification of the left lateral ventricle, a cysticercus cyst is evident (arrow). (Courtesy of Dr. Enrique Palacios, Berwyn).