This two-year-old boy presented with vomiting and lethargy. Axial pre (A) and post-contrast (B) TI MR images demonstrate a large mass within the temporal horn of the right lateral ventricle with lobulated margins and characteristic frond-like surface projections. There is homogeneous, intense enhancement after contrast administration (B). Associated marked hydrocephalus is noted. Axial unenhanced CT image (C) shows subtle calcifications within the lesion.
Choroid plexus papillomas (CPPs) are WHO grade I tumors which most commonly present in children under 5 years of age. Typical locations mirror the most prevalent locations of choroid plexus, to include the lateral and 4th ventricles. The atria of the lateral ventricle is the most common site in children, while the 4th ventricle is the most common site in adults. These lesions cause hydrocephalus primarily by overproduction of CSF; there is also likely some degree of impaired CSF resorption. CPPs are typically isointense on T1, iso- to hyperintense on T2, and enhance avidly. They are highly vascular with a vascular pedicle and flow voids often visible on T2 sequences. Calcification is seen in ≈25% of cases.
Complete surgical resection is curative and recurrences are uncommon. Choroid plexus carcinomas (CPCs) are WHO grade III lesions and are differential considerations for an avidly enhancing intraventricular mass in regions of choroid plexus. CPCs typically demonstrate aggressive characteristics, such as heterogeneous enhancement and parenchymal invasion; however, oftentimes, they may be indistinguishable from CPPs on imaging. Choroid plexus tumors are prone to CSF seeding; therefore, the entire neuroaxis should be imaged prior to surgical intervention.
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Toffoli TJ, O'Brien WT Sr. At the Viewbox: Choroid plexus papilloma. J Am Osteopath Coll Radiol. 2012;1(3):34.