CT - demonstrates a hyperdense structure in the lateral ventricle causing hydrocephalus in a young patient. Pathology revealed a choroid plexus carcinoma.
- Neoplasms of ventricular system are usually easy to recognize but pathology is sometimes difficult to determine by imaging characteristics
- Choroid plexus - found in the ventricles - highly vascular and produces CSF
- Choroid plexus neoplasms - usually highly vascular and produce hydrocephalus
- Benign - papilloma; Malignant - carcinoma
- Most frequently found in atria and posterior portion of lateral ventricles
- Other highly vascular tumors are commonly seen in this site - mets and meningioma
- Ependymal cells - ependymoma
- Subependymal glial cells - subependymomas and subependymal giant cell astrocytoma
- Septum pellucidum - central neurocytoma
- Choroid plexus - found most commonly in atria, third ventricle and 4th ventricle (not seen in temporal horns or aqueduct of Sylvius)
- 50% of tumors are in lateral ventricles, 40% in 4th and 5% in 3rd.
- Rare - extraventricular areas like CPA, suprasellar cistern etc
- Choroid plexus tumors aren't that common overall but 10-20% of brain tumors in those less than 1 yr.
- 80% are benign papilloma and rest are carcinoma
- Those in lateral ventricle are most likely to present <10
- Most present due to symptoms of hydrocephalus
- Other symptoms - cranial nerve palsies, seizures, coma, and one report of psychosis
- Choroid plexus tumors - have an association with Li-Fraumeni and Aicardi syndromes
- Choroid plexus papilloma - 5 yr survival - practically 100%
- Choroid plexus carcinoma - 5 yr survival - 26-50%
- Choroid plexus tumors - cauliflower like well circumscribed masses with lobulations
- hemorrhage and cyst formation can be seen
- Signs of carcinoma - necrosis and parenchymal invasion
- Lateral ventricle choroid plexus - attached at trigone
- 3rd ventricle - attached at roof
- 4th ventricle - attached at posterior medullary velum
- Can have ball-valve effect for hydrocephalus
- Atypical choroid plexus papilloma - one or 2 histologic malignant features but not enough for carcinoma
- Papilloma and Carcinoma (but much more frequent for carcinoma) can have seeding of CSF
- CT - most tumors are iso or hyperattenuating
- CT - with enhancement - avid enhancement
- CT - 24% see calcifications
- T1 MR - iso or hypo to brain
- T2 - variable and often see flow voids within the lesion
- T1 postcon - avid enhancement
- Carcinoma - may have more variable CT and MR appearance; may have less hydrocephalus; look for parenchymal invasion and vasogenic edema
- Carcinoma - Increased uptake on FDG PET
- Imaging - papilloma and carcinoma has a lot of overlap therefore unless obvious malignant features are present cannot exclude carcinoma when imaging looks like a papilloma
- Lateral ventricular lesions - supplied by anterior choroidal, medial posterior choroidal and lateral posterior choroidal arteries
- 4th ventricular - choroidal branches of PICA
- Lesions in trigone - less than 10 - think papilloma/carcinoma; 10-40 - think low grade glial like ependymoma or subependymoma; >/= 40 - think meningioma, mets, lymphoma
- Intraventricular meningioma - rare and almost always older (caveat - 1/5 of all meningiomas in children are intraventrciular)
References - http://radiographics.rsnajnls.org/cgi/content/full/22/6/1473 and http://www.ajnr.org/cgi/content/full/20/5/882
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