It is What It Isn't: Atypical and Unusual MR Imaging Presentations of Pediatric Ganglioglioma Suraj H. Rambhia, MD Peter Lee, MD Avery Wright, MD Mark Atlas, MD Christopher G. Filippi, MD

Disclosures of Filippi CG NIH/NCI 1R01CA161404-01A Coulter Foundation Grant Consultant, Syntactx Mentor, RSNA grant recipient, whose work is not included in this presentation KIWH grant

Gangliogliomas typically…

…are located in the temporal lobes,. are slow growing and solid, …are located in the temporal lobes, are slow growing and solid, are non-enhancing, are non-restricting on DWI, and produce no mass effect

Atypical Gangliogliomas…

…often have poorer clinical outcomes…

…and can present with varied 1. tumor signal. 2. peritumoral edema. 3 …and can present with varied 1. tumor signal 2. peritumoral edema 3. location 4. enhancement pattern 5. diffusion characteristics

We present a…

Retrospective, IRB-approved review of all pathology-proven pediatric gangliogliomas at our institution.

Typical vs Atypical ganglioglioma features:

Typical lack of enhancement, Wasek T1 POST T1 PRE FLAIR T2 14-year-old female with right medial temporal lobe cystic lesion (red arrows) demonstrated more typical lack of contrast enhancement, despite having atypical cystic properties. … but atypical cystic appearance

T1 FLAIR T1 POST Typical lack of mass effect or edema, however atypical nodular rim of enhancement T2 FLAIR T1 POST 14-month old-male presented with left sided temporal lobe mass (red arrows) with demonstrating atypical rim of enhancement with solid nodular enhancing component. There was no peritumoral edema or diffusion restriction.

11-year-old male demonstrated prominent T2 prolongation of the right anteromedial temporal lobe with solid enhancing nodule (T1-pre isointense), no diffusion restriction or mass effect. T1 T2 FLAIR Example of more typical lack of diffusion restriction, despite presence of more atypical solid enhancement. T1 POST DWI

More Atypical ganglioglioma features:

The presence of peritumoral edema is highly atypical.

13-year-old female demonstrated a focal solid nodule of the left primary somatosensory cortex with surrounding edema and no restricted diffusion. Findings suggest that the pattern of contrast enhancement and peritumoral edema are variable characteristics of ganglioglioma. AX T1 POST

They can have cystic and solid appearance, mimicking a JPA.

JPA mimic T1 PRE AX T1 POST COR T1 POST T2 T2 FLAIR DWI While classically ganglioglioma presents as a solid mass, coexistence of solid and cystic components are not uncommon. A 17-year-old female presented with a tiny primary motor cortex lesion, with cystic component superiorly and solid enhancing component inferiorly. The lesion was hyperintense on T2/FLAIR and isointense on DWI. T1 PRE AX T1 POST COR T1 POST T2 T2 FLAIR DWI

Another JPA?

T2 FLAIR FLAIR COR T1 AX T1+ AX T1+ COR T1+ 2-year-old male, presented with similar findings of a cystic left temporal lobe mass demonstrating abnormal T2 prolongation (yellow arrow) and solid nodular enhancing component (red arrows) that would more classicially resemble a juvenile pilocytic astrocytoma (JPA). Mild surrounding mass effect and no diffusion restriction. AX T1+ AX T1+ COR T1+

Multicentric Enhancement

Multicentric Enhancement AX T1 POST 11-year-old female with ganglioglioma of the left parahippocampal gyrus and amygdala. Numerous foci of enhancement (red arrows), almost with infarct like distribution of the PCA territory. Lesions were mildly T2 hyperintense and demonstrated no diffusion restriction. Confirmed WHO I Gangliogioma. COR T1 POST Kramer, Quinn T2 POST

Diffusion Restriction

Diffusion Restriction 7-year-old female presented with a solidly enhancing left temporal lobe tumor which was T2/FLAIR hyperintense and T1 hypointense (not shown) with unusual findings of diffusion restriction (red arrows) and surrounding mild mass effect on the left temporal horn (blue arrow). DWI T2 FLAIR T1 POST

Colloid Cyst? No.

Colloid Cyst Mimic T1 T2 FLAIR 17-year-old female demonstrated a rounded T1 isointense lesion of left foramen of Monroe causing obstructive hydrocephalus, which by description may sound like a colloid cyst, but was actually a pathology proven ganglioglioma.

Not a Bleed

T1 T2 FLAIR SWI FLAIR COR T1 POST 20-day-old female presented at unusually young age with a large well-marginated left frontoparietal subcortical mass abutting the lateral ventricle and demonstrating peripheral hyperintensity on T1, T2 hypontensity, FLAIR hyperintensity and enhancement on post contrast images. Differential diagnosis a priori would have included methemoglobin related pathology such as a subacute hemorrhage with underlying mass given the circumscribed nature of the finding. However, no susceptibility was demonstrated. Confirmed WHO I Gangliogioma. FLAIR COR T1 POST

Leptomeningeal Enhancement.

Leptomeningeal Enhancement. 16-year-old male with mixed cystic and solid lesion T2/FLAIR hyperintense and enhancing lesion of the left temporal lobe (red circles) with leptomeningeal enhancement of the left MCA territory extending to the left sylvian fissure (yellow arrows). Confirmed WHO I Gangliogioma. FLAIR T2 Jordan, Benjamin T1 POST

Weird location…

Suprasellar Mass T1 PRE 15-year-old male demonstrated a large heterogeneous, cystic suprasellar mass encasing surrounding vasculature and demonstrating multifocal regions of enhancement. T1 POST

Another weird location…

Midline Pineal Region / 3rd Ventricle Mass 12-year-old female presented with a midline mass centered in the pineal region but possibly intraventricular (third) as well. Midline Pineal Region / 3rd Ventricle Mass SAG T2

Cortical Dysplasia? I think not.

Cortical Dysplasia Mimic 22-month-old female demonstrated subtle non-enhancing focus of T2 prolongation and blurring of the gray-white junction of the right parietal cortex (yellow arrows). Given additional findings of subtle volume loss (blue arrows), suggestion of chronic subcortical ischemia was suggested on the initial reading. A dysembryoplastic neuroepithelial tumor could also have this type of appearance. T1 T2 FLAIR COR T1 COR T2

Just Plain Bizarre

T1 FLAIR T1 POST T1 POST DWI T1 FLAIR FLAIR 10-year-old male with NF1 presented with an expansile lesion of the left superior cerebellar peduncle (red circle) causing mild mass effect on the 4th ventricle (blue arrow) and demonstrating hyperintensity on T2/FLAIR, restricted diffusion (red arrow) and enhancement. The patient also had a presumably unrelated retrochiasmal mass (yellow arrows). Confirmed WHO I Gangliogioma. T1 FLAIR FLAIR

Summary Atypical MR imaging findings of ganglioglioma occur with greater frequency than expected, and recognition of atypical features may inform treatment planning given reports of poorer post-treatment and postsurgical outcomes in these cases.

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SURAJ H. RAMBHIA, MD PGY3, DEPARTMENT OF RADIOLOGY HOFSTRA NORTHWELL SCHOOL OF MEDICINE LONG ISLAND, NY SRambhia13@northwell.edu