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Central Neurocytoma


KEY FACTS

Terminology

  • Central neurocytoma (CN) = intraventricular neuroepithelial tumor with neuronal differentiation

Imaging

  • Best diagnostic clue: “Bubbly” mass in frontal horn or body of lateral ventricle

    • May involve 3rd ventricle

  • CT: Usually mixed solid and cystic mass with calcification

    • Hydrocephalus common

    • Rarely complicated by hemorrhage

  • MR: Heterogeneous, T2 hyperintense, “bubbly” appearance

    • May be predominantly solid mass

    • Moderate to strong heterogeneous enhancement

  • MRS: ↑ Cho, ↓ N -acetylaspartate; glycine peak at 3.55 ppm

  • If “bubbly,” “feathery,” or solid intraventricular mass near foramen of Monro in young adult, consider CN

Top Differential Diagnoses

  • Subependymoma

  • Subependymal giant cell astrocytoma

  • Intraventricular metastasis

  • Ependymoma

  • Choroid plexus papilloma

Clinical Issues

  • Young adults, commonly 20-40 years of age

  • Usually benign, local recurrence is uncommon

    • Surgical resection is typically curative

    • If incomplete resection, radiation therapy, chemotherapy, &/or radiosurgery may be helpful

  • 5-year survival rate: 90%

  • MIB-1 (Ki-67 labeling) index > 2-3% = poorer prognosis

  • Headache, increased intracranial pressure, mental status changes, seizure are most common presenting features

    • Hydrocephalus secondary to foramen of Monro obstruction

Axial graphic shows a circumscribed, lobular, “bubbly” mass
attached to the septum pellucidum
. Ventricular dilatation is related to foramen of Monro obstruction. This is the classic appearance of a central neurocytoma. Complete surgical resection is often curative for these WHO grade II tumors.

Axial NECT shows a heterogeneous mixed cystic/solid mass
in the lateral ventricles attached to the septum pellucidum. There is associated obstructive hydrocephalus
, typical for central neurocytoma.

Axial T2WI MR in a 20 year old with headaches shows a predominantly solid ventricular mass in the body of the lateral ventricle
attached to the septum pellucidum with prominent flow voids
.

Axial T1WI C+ MR in the same patient shows diffuse enhancement
. Central neurocytoma was diagnosed at resection. Imaging differential considerations include subependymal giant cell astrocytoma, subependymoma, and meningioma.

(Courtesy S. van der Westhuizen, MD.)

TERMINOLOGY

Abbreviations

  • Central neurocytoma (CN)

Synonyms

  • Neurocytoma

Definitions

  • Intraventricular neuroepithelial tumor with neuronal differentiation

  • Well-demarcated, intraventricular, neurocytic neoplasm located in foramen of Monro region

IMAGING

General Features

  • Best diagnostic clue

    • “Bubbly” mass in frontal horn or body of lateral ventricle

  • Location

    • Typically supratentorial, intraventricular

    • Intraventricular mass attached to septum pellucidum

      • –

        > 50% in frontal horn/body of lateral ventricle, near foramen of Monro

      • –

        15% extend into 3rd ventricle

    • Both lateral ventricles: 13%

    • 3rd ventricle only: ~ 5%

    • 4th ventricle: Extremely rare

    • Rare extraventricular tumors with neurocytoma features (extraventricular neurocytoma)

      • –

        Brain parenchyma, cerebellum, brainstem, spinal cord

  • Size

    • Variable

  • Morphology

    • Circumscribed, lobulated mass with intratumoral “cysts”

    • Characteristic bubbly appearance on imaging studies

    • May be predominantly solid

CT Findings

  • NECT

    • Usually mixed solid and cystic (iso-/hyperdense)

    • Ca++ common (50-70%)

    • Hydrocephalus common

    • Rarely complicated by hemorrhage

  • CECT

    • Moderate heterogeneous enhancement

MR Findings

  • T1WI

    • Heterogeneous, mostly isointense to gray matter

    • Cysts are hypointense

    • Prominent flow voids may be seen

    • Hemorrhage is rare

  • T2WI

    • Heterogeneous, hyperintense bubbly appearance

    • Associated hydrocephalus is common

    • Ca++ often hypointense

    • Prominent flow voids may be seen

  • PD/intermediate

    • Heterogeneous, predominantly hyperintense mass

    • Prominent flow voids may be seen

  • FLAIR

    • Heterogeneous, predominantly hyperintense mass

  • T2* GRE

    • Ca++ seen as areas of “blooming”

  • T1WI C+

    • Moderate to strong heterogeneous enhancement

  • MRS

    • Elevated Cho peak, decreased NAA typical

    • Glycine peak at 3.55 ppm typical

    • Alanine peak may be seen

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