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Computed tomography
Magnetic resonance imaging
UltrasonographyInitial CT of the head (1/11/96) revealed a homogeneous, slightly hyperdense, frond-like mass in the posterior horn of the left lateral ventricle. There is hydrocephalus with marked ventricular enlargement, right more than left. Contrast administration demonstrates intense homogeneous enhancement of the mass.
MR evaluation the same day again shows the homogeneous mass in the posterior horn of the left lateral ventricle. This mass appears slightly hypointense on the T1-weighted images. A midline sagittal image shows communicating hydrocephalus with enlargement of the ventricles and cisterns. T2-weighted images show the mass to be slightly hyperintense in respect to white matter.
This baby also had ultrasound evaluation as a baseline study for postsurgical follow-up the next day, which again demonstrated the intraventricular mass. Color Doppler images demonstrate the hypervascularity of the mass.
Patients present with signs of increased intracranial pressure, including vomiting, clumsiness, headaches, and seizures. The tumors are frequently located in the glomus of the choroid plexus in the atrium/trigone of the lateral ventricles. In children, they are much more frequent on the left than on the right. In adults, they are frequently located in the fourth ventricle and cerebello-pontine angles. They are rare in the third ventricle. The tumors are multiple in 7% of patients. Because the choroid plexus develops embryologically from arachnoid, pia, and ependymal origins, the differential diagnosis includes choroid plexus carcinoma, interventricular meningioma, ependymoma, metastases, cavernous angioma, xanthogranuloma, and astrocytoma.
Pathologic specimens demonstrate a large aggregation of choroidal fronds producing CSF arising from normal choroid plexus epithelial cells. The masses frequently have smooth lobulated borders, small foci of calcifications, and engulf the glomus of the lateral ventricle. There is asymmetric diffuse ventricular dilatation related either to CSF overproduction or decreased absorption due to arachnoid regulation obstruction from repeated occult hemorrhage and/or micrometastases. Temporal horn dilatation can be seen ipsilaterally on the side of the atrial tumor. Rarely, there is growth into the surrounding white matter, which is more common with choroid plexus carcinoma.
These images demonstrate the typical CT anbd MR appearance of a choroid plexus papilloma. The mass is iso- to midly hyperdense with homogeneous enhancement on the contrast-enhanced CT. It can be characterized by accompanying calcification and ventricular dilatation. The MR appearance is isointense to slightly hypointense on T1-weighted images and slightly hyperintense on T2-weighted images relative to the white matter. Invasive papillomas or carcinomas are more often heterogeneous with irregular enhancement. On ultrasound, an echogenic mass inseparable from the choroid plexus can be seen. Angiography demonstrates anterior and posterior choroidal artery supply off the internal carotid to this highly vascular tumor.
Complications include hydrocephaus, transformation into malignant choroid plexus carcinoma, and drop spinal cord metastasis. The tumors are treated with surgical removal; operative mortality is high due to the vascularity of the tumor. Radiotherapy and chemotherapy is restricted to tumors with malignant features or those that recur after surgery. Postsurgical complications include subdural hemorrhage and the need for ventriculoperitonal shunting.
Swaiman K. Pediatric Neurology. Principles and Practice. 2nd Ed. St. Louis: Mosby, 1994: pp. 891, 960.
Brain Imaging. In: Wolpert SM, Barnes, PD. MRI in Pediatric Neuroradiology. St. Louis: Mosby, 1992: Chapters 3-8.
Ramsey RG. Neuroradiology. 3rd Ed. Philadelphia: W.B. Saunders, 1994: pp. 254, 279-280, 506.