Multiple Colloid Cysts: Case Report and Literature Review

Colloid cysts usually occur in the anterior third ventricle at the level of the foramina of Monro. Colloid cysts may extend from the third toward the lateral ventricle. We present a rare case of multiple intraventricular colloid cysts, two of which were in the third ventricle and one in the lateral ventricle.

A 40-year-old female patient presented with three intraventricular cystic lesions: one cyst in the typical localization in the anterior rostral third ventricle, another cyst behind it in the same (third) ventricle, and a larger bulging cyst in the right lateral ventricle. A bilateral ventriculoperitoneal shunt had been inserted 26 years before to treat hydrocephalus. All three cysts had different magnetic resonance imaging (MRI) signal characteristics. We removed the cysts through an endoscopically assisted right transcortical transventricular microsurgical approach, using the right ventricular catheter as a guide to the lateral ventricle. After removal of the lateral ventricular cyst, we observed that the foramen of Monro was greatly enlarged (most likely as a result of the large cyst), which allowed us to remove the cysts in the third ventricle. During surgery, the cysts were found to have different consistencies. MRI 2 years following surgery showed complete removal and no hydrocephalus. The patient had no symptoms, and the clinical examinations were normal.

Colloid cysts may become large and extend to the lateral ventricle, especially in patients treated with ventriculoperitoneal shunts. Studying the relevant pathoanatomy of these cysts is very important for preoperative planning including the choice of surgical approach.