MR Imaging and Clinical Characteristics of Diffuse Glioneuronal Tumor with Oligodendroglioma-like Features and Nuclear Clusters

Abstract

Background and purpose: Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC) is a new, molecularly defined glioneuronal CNS tumor type. The objective of the present study was to describe MR imaging and clinical characteristics of patients with DGONC.

Materials and methods: Preoperative MR images of 9 patients with DGONC (median age at diagnosis, 9.9 years; range, 4.2-21.8 years) were reviewed.

Results: All tumors were located superficially in the frontal/temporal lobes and sharply delineated, displaying little mass effect. Near the circle of Willis, the tumors encompassed the arteries. All except one demonstrated characteristics of low-to-intermediate aggressiveness with high-to-intermediate T2WI and ADC signals and bone remodeling. Most tumors (n = 7) showed a homogeneous ground-glass aspect on T2-weighted and FLAIR images. On the basis of the original histopathologic diagnosis, 6 patients received postsurgical chemo-/radiotherapy, 2 were irradiated after surgery, and 1 patient underwent tumor resection only. At a median follow-up of 61 months (range, 10-154 months), 6 patients were alive in a first complete remission and 2 with stable disease 10 and 21 months after diagnosis. The only patient with progressive disease was lost to follow-up. Five-year overall and event-free survival was 100% and 86±13%, respectively.

Conclusions: This case series presents radiomorphologic characteristics highly predictive of DGONC that contrast with the typical aspects of the original histopathologic diagnoses. This presentation underlines the definition of DGONC as a separate entity, from a clinical perspective. Complete resection may be favorable for long-term disease control in patients with DGONC. The efficacy of nonsurgical treatment modalities should be evaluated in larger series.

FIGURE.

Representative MR imaging slices of all 9 patients (P1–P9). Columns: A, Axial T2WI in all MRIs; B, Coronal T2WI (P1, P2, P5) and coronal FLAIR (P3, P4, P6, P7, P8, P9); C, Contrast-enhanced T1WI, sagittal (P1, P2, P5), axial (P3, P6, P8, P9), or coronal (P4, P7); D, axial DWI/ADC in all MRIs. Long gray arrows, centrally decreased T2 signal suggestive of diffuse calcification (P1A, P2A); black arrows, tumor encompassing the circle of Willis and adjacent arteries without compression (P1AB, P2B, P5B, P9B); short gray/white arrows, marked edema (P3A); short white arrows, bandlike pattern with intermediate signal on T2WI (P3A, P8A); short gray/black arrows, inhomogeneous band-like CE of the solid tumor part (P3C, P8C); white asterisk, restricted diffusion (P4D); white arrow, patchy pattern of CE affecting <25% of the tumor volume (P9C).

FIGURE.

Representative MR imaging slices of all 9 patients (P1–P9). Columns: A, Axial T2WI in all MRIs; B, Coronal T2WI (P1, P2, P5) and coronal FLAIR (P3, P4, P6, P7, P8, P9); C, Contrast-enhanced T1WI, sagittal (P1, P2, P5), axial (P3, P6, P8, P9), or coronal (P4, P7); D, axial DWI/ADC in all MRIs. Long gray arrows, centrally decreased T2 signal suggestive of diffuse calcification (P1A, P2A); black arrows, tumor encompassing the circle of Willis and adjacent arteries without compression (P1AB, P2B, P5B, P9B); short gray/white arrows, marked edema (P3A); short white arrows, bandlike pattern with intermediate signal on T2WI (P3A, P8A); short gray/black arrows, inhomogeneous band-like CE of the solid tumor part (P3C, P8C); white asterisk, restricted diffusion (P4D); white arrow, patchy pattern of CE affecting <25% of the tumor volume (P9C).