Choroid Plexus tumors arise from the epithelium of hte choroid plexus of the cerebral ventricles. They are graded in 3 WHO grades:
They generally present within the first two years of life and account for 2% - 4% of all brain tumors in children, but as many as 10% of those in the first year of life. In children, most choroid plexus tumors arise in the lateral ventricles causing obstruction of CSF flow. Infants commonly present with increasing head circumference and older children with signs of ICP. Lesions are typically hyperdense, contrast-enhancing masses. They can and do seed into the CSF space and workups should include MRI/gad cranio-spinal axis imaging and CSF cytology.
Grade I papillomas account more more than half of these tumors and are frond-like with delicate fibrovascular tissue covered by a single layer of uniform cuboidal columnar epithelial cells. with round or oval basally situated nuclei. Increased mitotic activity shifts the grade to a Grade II. Grade III choroid plexus carcinomas are solid tumors that tend to broach the ventricular wall and invade the brain. Histologically Grade III CPC's show f
The general workup includes a complete history and physical exam, MRI of the brain and spine and CSF cytology.
Surgery is the mainstay of choroid plexus treatments for both primary and metastatic lesions. Complete resection is frequently achieved with excellent outcomes. Less than 10% recur and overall survival is close to 100%.
The role of radiation therapy after incomplete resection is unclear since not all patients will progress. Observation without adjuvant treatment is a preferred strategy with consideration of re-resection if feasible. Radiotherapy is reserved for treatment of inoperable progression.
Surgery is an important component of treatment, but frequently more difficult than in papillomas. Blood loss is considerable and staged procedures may be necessary to obtain an optimal resection. In most studies, results are better for patients who have undergone a complete resection. If a complete resection is achieved, it is not clear that there is a benefit to adjuvant treatment. One report indicates results are better with adjuvant radiation, Perez noting that the pooled series was biased with more unfavorable disease cases. Others have reported excellent results with complete resection without adjuvant radiation ± chemotherapy.
For patients with less than complete resections, outcomes are significantly worse. The role of radiation in the setting of incomplete resection remains controversial. There are efforts underway to examine the role of genetic markers in helping make a determination to offer adjuvant radiation. TP53 carriers do worse and therefore may benefit more from adjuvant radiation than normal types.
Radiotherapy in choroid plexus cancers is controversial, and so is the target volume. More than half of the failures in patients treated to the local disease site only occured outside of the radiation field. CSI was traditionally used and a recent literature review reported that CSI as associated with improved PFS when compared with tumor directed radiation. This controversy is especially troubling given the young age of these patients and the well known late effect toxicity of radiation in this population. At present, unless there is clear evidence of leptomeningeal seeding, it would still be considered reasonable to limit dose to the GTV + margin. (Freeman, writing in Perez, 6th ed, p.1645)