Choroid plexus papilloma and carcinoma

Incidence

They represent 2-5% of all intracranial neoplasms in children. In adults they are rare.

Origin

Choroid plexus tumors arise from the epithelium of the choroid plexus.

Macroscopic appearance and general characteristics

Choroid plexus papillomas are exophytic (cauliflower-like) intraventricular masses. Limited infiltration of the underlying brain parenchyma is occasionally seen. They manifest by obstruction of CSF pathways or by excessive production of CSF. The lesion is benign and slow growing. The most common location is the trigone of the lateral ventricle (60%) and the fourth ventricle (40%).

They occur in very young children under 2 years of age and in adults. Choroid plexus papilloma is Grade I, carcinoma corresponds to Grade III.

Microscopic appearance (images 2 - 3)

Choroid plexus papilloma is an epithelial tumor, composed of a simple or pseudostratified layer of cuboidal to columnar cells, resting on a basement membrane, overlying papillary fibro-vascular cores.

Imaging features (see case reports)

- On non-contrast CT, most choroid plexus papillomas are hyperdense, with calcification in one out of four lesions.

- On MRI the lesion is isointense on T1 WI and slightly hyperintense on T2 WI (image 4). Hypervascularity can be reflected by signal voids. Enhancement again is marked.

- Imaging features do not allow one to distinguish benign from malignant lesions.

Differential diagnosis

In a child the differential diagnosis includes medulloblastoma, choroid plexus carcinoma, ependymoma and astrocytoma.

In adults the major differential diagnoses includes metastasis and meningioma.

Case reports

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Choroid plexus papilloma

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