Typical Choroid Plexus Papilloma

KEY FACTS

TERMINOLOGY

• Choroid plexus tumor (CPT)

○ 3 types of CPTs

– Choroid plexus papilloma (CPP) (WHO grade I)

– Atypical CPP (aCPP) (grade II)

– Choroid plexus carcinoma (CPCa) (grade III)

IMAGING

• Classic: Child with enhancing lobulated (cauliflower-like)

mass in atrium of lateral ventricle

• CPPs occur in proportion to amount of choroid plexus

○ 50% in lateral ventricle (usually atrium)

○ 40% in 4th ventricle &/or foramina of Luschka

○ 5% in 3rd ventricle (roof)

• Hydrocephalus (overproduction, obstructive)

TOP DIFFERENTIAL DIAGNOSES

• aCPP

• CPCa

• Physiologic choroid plexus enlargement

• Choroid plexus xanthogranuloma

• Meningioma

• Intraventricular metastasis

• Medulloblastoma

• Ependymoma

CLINICAL ISSUES

• Most common brain tumor in children < 1 year old

○ 13.1% of all brain tumors in 1st year of life

○ 7.9% of fetal brain tumors diagnosed by ultrasound

• Benign, slowly growing

○ ± cerebrospinal fluid spread (does not distinguish CPP

from CPCa)

○ Malignant progression rare

DIAGNOSTIC CHECKLIST

• Consider CPP if intraventricular mass in child < 2 years old

• Imaging cannot reliably distinguish CPP from aCPP, CPCa

(Left) Axial graphic shows a

choroid plexus papilloma

(CPP) arising from the glomus

of the left lateral ventricular

trigone. Note the

characteristic frond-like

surface projections ﬊. CPPs

are most common in the

lateral ventricles of a child.

(Right) Axial NECT in a child

with macrocephaly shows

hydrocephalus with a

lobulated mass st in the

atrium of the left lateral

ventricle.

(Left) Axial T2WI MR in the

same patient shows a

heterogeneously hyperintense

lateral ventricle mass with

scattered hypointense flow

voids ﬈, indicating high

vascularity. The lobulated

nature of the mass is striking.

(Right) Axial T1WI C+ MR in

the same case shows marked

enhancement of the lobular

mass with frond-like

projections, characteristic of

CPP. CPP cannot be reliably

differentiated from atypical

CPP by conventional imaging

alone.

Brain: Pathology-Based Diagnoses: Neoplasms,

Cysts, and Disorders

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