Objective and importance: The case of a 42-year-old woman with a choroid plexus papilloma (CPP) arising from the posterior wall of the third ventricle is described. This case is very unusual because the tumor did not have any connection with the choroid plexus but was attached to the normal brain parenchyma.
Clinical presentation: The patient presented with the symptoms of increasing intracranial pressure. Magnetic resonance imaging revealed hydrocephalus related to a small mass in the posterior third ventricle, occluding the aqueduct.
Intervention: Surgery confirmed that the tumor was located at the surface of the posterior commissure without having any connection to the normal choroid plexus. A histopathological examination revealed a CPP with no attachment to the choroidal tissue.
Conclusion: A review of the literature demonstrates that CPPs without any connection to the choroid plexus are very unusual. To our knowledge, this is the first reported case of such a CPP that developed on the posterior wall of the third ventricle in which no choroid plexus was present. Furthermore, this tumor, to our knowledge, is also the smallest intraventricular CPP to be verified at surgery.