Diffuse glioneuronal tumor with oligodendroglioma like features and nuclear clusters

Diffuse glioneuronal tumor with oligodendroglial features and nuclear clusters is a glioneuronal tumor entity with a characteristic methylation profile ¹.

Terminology

The exact nature of diffuse glioneuronal tumors with oligodendroglial features and nuclear clusters has yet to be well defined. In fact, its histological features almost overlap with other better-known tumors such as oligodendroglioma grade 3 and primitive neuroectodermal tumors ¹.

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

Epidemiology

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

Pathology

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

Location

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

Microscopic appearance

Diffuse glioneuronal tumor 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 edema

• T1 C+ (Gd): poor enhancement ³

Treatment and prognosis

Data about the treatment and prognosis of these tumors 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 tumor (DNET)

• primitive neuroectodermal tumors

• glioblastoma