# A unique case of extra-cerebral diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters

## TL;DR

A rare brain tumor typically found in children was discovered in an adult in an unusual location, highlighting the need for radiologists to consider this diagnosis in atypical cases.

## Contribution

This paper reports the first known case of DGONC in an adult and an extra-cerebral location, expanding its clinical and radiological understanding.

## Key findings

- DGONC was found in a 40-year-old male in the temporal lobe and sacral region, outside typical pediatric supratentorial locations.
- The tumor exhibited oligodendroglioma-like features, synaptophysin and OLIG2 positivity, and no widespread GFAP staining.
- Imaging findings resembled a chronic inflammatory process, emphasizing the need for DGONC to be considered in atypical cases.

## Abstract

Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC) is a newly recognized provisional entity in the fifth edition of the WHO Classification of Central Nervous System Tumors, typically found in pediatric patients with supratentorial disease. We describe a male in his forties who presented with recurrent seizures and was found to have a heavily calcified lesion in the left temporal lobe and an additional lesion in the sacral region of the thecal sac; tissue biopsy of the sacral lesion demonstrated an oligodendroglioma-like morphology, strong synaptophysin and OLIG2 expression, and absent widespread GFAP staining, consistent with DGONC. This represents an unusual occurrence of DGONC outside the supratentorial region, with imaging findings that mimicked a chronic inflammatory process. Radiologists should be aware of the potential for DGONC to present in atypical locations and should consider it in the differential diagnosis of apparently non-neoplastic lesions.