Choroid plexus carcinoma (CPC) represents one of the most aggressive entities within the spectrum of central nervous system tumors, originating from the epithelial cells of the choroid plexus. These cells are responsible for producing cerebrospinal fluid (CSF), and when malignant, the tumor disrupts this vital function while exerting significant mass effect and obstructive hydrocephalus. Classified under the World Health Organization grade IV, this neoplasm is distinct from the more common choroid plexus papilloma due to its invasive nature, rapid growth, and potential for metastasis within the CSF pathways, a process known as drop metastasis.
Clinical Presentation and Diagnostic Pathway
The clinical manifestations of choroid plexus carcinoma are primarily driven by two mechanisms: the physical bulk of the tumor and the pathological production of CSF. Infants and young children, the most common demographic affected, typically present with rapidly increasing head circumference, bulging fontanelles, vomiting, and irritability due to obstructive hydrocephalus. In older children and adults, symptoms may include headaches, nausea, lethargy, and focal neurological deficits depending on the tumor's location, often within the lateral or fourth ventricles. The diagnostic journey begins with neuroimaging, where computed tomography (CT) scans frequently reveal a hyperdense, intraventricular mass with heterogeneous enhancement and possible areas of necrosis or hemorrhage.
Imaging and Molecular Characterization
Magnetic resonance imaging (MRI) provides superior delineation of the tumor's extent, its relationship to critical structures, and the presence of CSF dissemination. Typical MRI findings include intense contrast enhancement, invasion into adjacent brain parenchyma, and restricted diffusion on apparent diffusion coefficient (ADC) maps. While imaging is highly suggestive, definitive diagnosis relies on histopathological examination following surgical resection or biopsy. The molecular landscape of CPC has evolved significantly; beyond the common TP53 mutations seen in atypical teratoid/rhabdoid tumors, specific alterations in genes regulating chromatin remodeling and cell cycle control are increasingly identified, refining prognostic stratification and guiding therapeutic approaches.
Multimodal Treatment Strategy
The cornerstone of management for choroid plexus carcinoma is maximal safe surgical resection, which serves multiple purposes: obtaining tissue for diagnosis, reducing tumor burden to alleviate obstructive hydrocephalus, and potentially improving outcomes. Complete resection is often challenging due to the tumor's infiltrative behavior and location near eloquent brain areas, necessitating a balance between aggressiveness and neurological preservation. Following surgery, the standard of care involves adjuvant therapy, which typically consists of combined chemotherapy and craniospinal irradiation. Chemotherapy regimens, such as carboplatin and etoposide, are employed to target microscopic disease and control systemic or CSF spread, while radiation therapy addresses the entire neuraxis to prevent or treat metastatic deposits.
Addressing the Youngest Patients
A critical and nuanced aspect of treating choroid plexus carcinoma occurs in infants under the age of three. Due to the severe long-term neurocognitive sequelae associated with cranial irradiation in this population, oncologists often employ innovative strategies to delay or reduce radiation exposure. Intensive chemotherapy regimens, sometimes utilizing autologous stem cell rescue, are utilized to shrink the tumor and control disease while the child develops, with the goal of deferring radiotherapy until an older age when the brain is more resilient to its toxic effects. Clinical trials are essential for this demographic, evaluating novel drug combinations and targeted agents to improve survival while minimizing late effects.
Prognosis and Long-Term Management
Despite aggressive multimodal therapy, the prognosis for choroid plexus carcinoma remains guarded, with overall survival rates varying based on age, extent of resection, and response to adjuvant treatment. Five-year survival rates for children are estimated in the range of 40% to 60%, highlighting the need for continued research. Long-term management extends beyond survival, focusing on surveillance for recurrence, rehabilitation for neurological deficits, and monitoring for complications related to treatment. Survivors face significant risks, including endocrine dysfunction, cognitive impairment, and secondary malignancies induced by radiation and chemotherapy, necessitating a lifetime of coordinated care by a specialized neuro-oncology team.
