Abstract
Background and Study Aim 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.
Clinical Description 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.
Conclusions 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.
Keywords
colloid cyst - multiple - lateral ventricle
