Choroid plexus tumors (CPTs) are rare intraventricular neoplasms that primarily occur in children and are rare in adults. Of the CPT subtypes, choroid plexus carcinomas (CPC) are highly aggressive and malignant and of World Health Organization (WHO) Grade III. Dissemination through the cerebrospinal fluid space is the inevitable natural course of the disease. In this case report, we present a 33-year-old female with a past medical history notable for schizophrenia and bipolar disease who suffered from left-sided acute vision loss and hearing loss. Magnetic resonance imaging (MRI) demonstrated multiple enhancing masses found in the left cerebellopontine angle (CPA), right internal auditory canal, the atrium of the left ventricle, and the left foramen of Monroe. After surgical decompression of the CPA tumor, the permanent final pathology was consistent with CPC. To our knowledge, this is the first reported case of a primary CPC occurring within the CPA in an adult. The unique presentation and progression of this rare adult-onset CPC provide insight for the diagnosis and treatment of other rare instances of CPTs.

This chapter discusses six rare tumors of the central nervous system in adults: medulloblastoma in adults, cerebellar liponeurocytoma, diffuse leptomeningeal glioneuronal tumor (DLGNT), ganglioglioma, pineal parenchymal tumors, and pleomorphic xanthoastrocytoma (PXA). The incidence, clinical characteristics, histology, radiographic details, treatment, and outcomes are outlined for each disease. Magnetic resonance imaging (MRI) characteristics are provided for each tumor type. Importantly, following the 2016 World Health Organization (WHO) classification of brain tumors, the molecular profile of each tumor type is provided. Current knowledge on molecular advancements within the study of each of these tumors is reviewed and is a key theme as new molecular discoveries are incorporated into evolving treatment approaches. Multidisciplinary management, often at centers with specialized neuro-oncology providers, is recommended for these rare tumors. References are provided for more detailed information.