Diffuse glioneuronal tumor with oligodendroglioma like features and nuclear clusters

Diffuse glioneuronal tumour with oligodendroglial features and nuclear clusters is is a novel glioneuronal tumour entity recently identified bywith a characteristic methylation profile ¹.

Terminology

The exact nature of diffuse glioneuronal tumours with oligodendroglial features and nuclear clusters has yet to be well defined. In fact, its histological features almost overlap with other better-known tumours such as oligodendroglioma grade 3 and primitive neuroectodermal tumours¹.

It has been provisionally included in the 5^th Edition (2021)WHO brain tumour classification², but but more studies are needed for full acceptance. It has been proposed it should be considered a WHO grade 2 tumour ¹.

Epidemiology

Diffuse glioneuronal tumour with oligodendroglial features and nuclear clustersoccurs mainly in children, although some higher-age cases have been described ^{1, 3}.

Pathology

Diffuse glioneuronal tumour with oligodendroglial features and nuclear clusters demonstrates histological, molecular and immunophenotype features reminiscent of a wide spectrum of tumours, such as oligodendroglioma grade 3, neurocytoma,dysembryoplastic neuroepithelial tumortumour (DNET),primitive neuroectodermal tumours and even glioblastoma^{1, 3}. Therefore Therefore it is likely that in the near future many previously diagnosed high-grade CNS tumours will be re-assigned to this new entity based on its specific methylation profile.

Location

It arises in the cerebral hemispheres, preferentially from the temporal lobes ¹.

Microscopic appearance

Diffuse glioneuronal tumour with oligodendroglial features and nuclear clusters demonstrates clear cell features with moderate to high cellularity and diffuse infiltration, round nuclei with oligodendroglioma-like perinuclear halos, nuclear clusters and vascular proliferation ¹.

Immunophenotype

• MAP2: positive

• GFAP: negative

Radiographic features

MRI

• T1: hypointense

• T2/FLAIR:hyperintense with no perilesional oedema

• T1 C+ (Gd): poor poor enhancement ³

Treatment and prognosis

Data about the treatment and prognosis of these newly characterised tumours are still limited. In the few reported cases ^1,3, surgical resection was the treatment of choice with adjuvant radiation therapy and chemotherapy. Prognosis is generally positive although recurrence is possible.

Differential diagnosis

Possible imaging differential considerations include:

• oligodendroglioma

• neurocytoma

• dysembryoplastic neuroepithelial tumortumour (DNET)

• primitive neuroectodermal tumours

• glioblastoma