Evaluation of Supratentorial Choroid Plexus Tumors in Children

Examination

• Elevated ICP: Signs of chronic elevated ICP such as dilatation of scalp veins, bulging fontanelle, sunset gaze, and papilledema are generally present.
• Some developmental delay: Developmental delay may be global, or may specifically affect gross motor skills or walking.
• No focal neurological signs: Usually children with these tumors have no focal neurological signs.

Laboratory Tests

• Standard: Standard preoperative blood tests should be performed, but no abnormalities are expected.
• Type and crossmatch: It is necessary to type and crossmatch packed red blood cells in preparation for inevitable bleeding at surgery.

Radiologic Tests

CT scan

• Initial assessment: A CT scan is often done as the first assessment in the emergency room, especially when MRI is unavailable.
• Tumors of mixed density: Choroid plexus papillomas are usually iso- or hypodense.  Choroid plexus carcinomas may be slightly more hyperdense because of increased cellular content, and more heterogeneous. They both enhance with contrast.
• Cysts and calcium: The tumors are occasionally cystic, and cysts have CSF density.  Microcalcifications are present in 25% of tumors.
• Irregular margins: The tumor margins are slightly irregular for both choroid plexus papillomas and choroid plexus carcinomas; they are commonly multilobular.

CT scan of choroid plexus carcinoma:

MRI

MRI is the study of choice.

• T1-weighted MRI: The tumor is lobulated, isointense or hypointense, with some calcifications.
• T2-weighted MRI: The tumor is of heterogeneous hyperintensity.
• Contrast enhancement: The tumor enhances with gadolinium.
• Invasion: Both choroid plexus papillomas and choroid plexus carcinomas can show parenchymal invasion.
• Cysts: Cysts will have CSF intensity, sometimes slightly more intense on T2-weighted images than CSF.
• Edema: There is usually more peritumoral vasogenic edema in choroid plexus carcinomas, as well as more heterogeneous edema (hemorrhagic and cystic areas).
• Other: Large blood vessels might be seen or identified because of signal voids.
• Metastases: Metastases are usually seen as nonspecific enhanced lesions.

T1-weighted axial MRI with gadolinium enhancement of a choroid plexus papilloma:

T1-weighted sagittal MRI with gadolinium enhancement of a choroid plexus papilloma:

Angiography

• Embolization: Embolization may be planned as part of the angiographic procedure, as it may reduce the blood loss associated with removal of choroid plexus tumors.
• Anterior choroidal artery – lateral ventricle tumors: Tumors situated in the atrium and the temporal horn of the lateral ventricles are vascularized by the anterior choroidal artery as well as the medial and lateral posterior choroidal arteries.
• Branches of the middle cerebral artery – large tumors: If large, the tumor may receive vascularization directly from branches of the middle cerebral artery.
• Lateral posterior choroidal artery: Tumors situated in the temporal horn and body of the lateral ventricle might also receive tributaries from the lateral posterior choroidal artery.
• Medial posterior choroidal artery – third ventricle: Tumors situated in the third ventricle receive tributaries from the medial posterior choroidal artery.
• PICA +/-, AICA, and SCA – fourth ventricle tumors: Tumors in the fourth ventricle are vascularized by choroidal branches of the PICA and sometimes also by the AICA and the SCA.

Nuclear Medicine Tests

• PET scan reportedly used to differentiate choroid plexus papillomas from gliomas: PET studies have been published as case reports for choroid plexus papillomas and have shown these tumors to have a different uptake from gliomas (29). While PET has been reported to be correlated with malignancy, there are no specific studies showing that nuclear medicine studies can differentiate between a papilloma and carcinoma.

Electrodiagnostic Tests

• Not useful

Neuropsychological Tests

• Signs of developmental delay: The use of developmental scales may reveal some global delay, or specific delays in motor coordination, walking, and the like.

Correlation of Tests

• Appearance on imaging and vessel supply: The location of the tumor on the CT/MRI scans and the location of the major feeding arterial supply to the tumor are used to determine the best surgical approach. The surgical approach should ideally allow access to the major arterial supply early in the operation to avoid excessive blood loss.