anaplastic oligodendroglioma

Occipital
anaplastic oligodendroglioma with multiple organ metastases after a short clinical course: a case report and literature review. Representative axial MR images with gadolinium, taken on initial admission. (A) T1-weighted MR image (T1WI); (B) Contrast-enhanced T1WI and (C) T2-weighted MR image (T2WI) showing a left occipital tumor with mild contrast enhancing; (D) at one month follow up, T1WI; (E) contrast-enhanced T1WI and (F) T2WI showing no apparent enhanced lesion; (G) 8 months later after the first surgery, T1WI; (H) contrast-enhanced T1WI and (I) T2WI showing marked enhanced mass on the cavity and recurrence; (J) 48 h after the second surgery, T1WI; (K) contrast-enhanced T1WI, and (L) T2WI showing no apparent enhanced lesion; (M) 8 months later after combination radiotherapy and chemotherapy, T1WI; (N) contrast-enhanced T1WI and (O) T2WI showing marked enhanced mass of the wall in the posterior portion of the removal cavity and left temporal areas, and recurrence of the enhanced tumor. (P, Q) 8 months later after combination radiotherapy and chemotherapy, sagittal spinal contrast-enhanced T1WI after gadolinium infusion showing high-intensity mass lesion in (P) T7, T10, and T12 vertebral bodies (arrowheads) and (Q) T12, L2, L3, L5, and S1 vertebral bodies (arrows).
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Anaplastic oligodendroglioma is a WHO grade III diffuse infiltrating glioma that has histological features of anaplasia, and molecular markers consistent with an oligodendroglioma (1p19q co-deletion and IDH mutation) as per the current (2016) WHO classification of CNS tumors . They make up 20-50% of all oligodendrogliomas. If the molecular status is unavailable then the diagnosis relies on histology alone and is given the designation anaplastic oligodendroglioma NOS.

Epidemiology

Anaplastic oligodendrogliomas tend to present in a slightly older age group than WHO grade II tumor, presumably on account of them having been undiagnosed for some time.

Clinical presentation

Clinical presentation is non-specific with symptoms related to increased intracranial pressure and focal neurological deficits being common. Seizures are also fairly common, but not as common as with WHO grade II oligodendrogliomas .

Pathology

Anaplastic oligodendrogliomas demonstrate increased cellular density, increased mitotic activity, microvascular proliferation and necrosis.  Nuclear anaplasia is also common.

Importantly, and unlike astrocytomas, oligodendrogliomas with necrosis and microvascular proliferation are considered only WHO grade III anaplastic oligodendrogliomas and not WHO grade IV glioblastomas . In other words, if you have a tumor that is both IDH mutated and 1p19q co-deleted you can never call it a glioblastoma. Having said that occasionally IDH wild-type glioblastomas may have 1p19q deletions.

Radiographic features

The radiographic features of anaplastic oligodendrogliomas are highly variable and range from those of oligodendrogliomas to glioblastomas. Generally, they demonstrate more intense contrast enhancement and more heterogeneity than lower grade tumors .

Treatment and prognosis

Prognosis with maximal surgical and medical management is significantly poorer than WHO grade II oligodendrogliomas but better than anaplastic astrocytomas . Again, the recent change in classification makes interpretation of survival data difficult, given most of it does not report molecular markers.

Siehe auch:
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Assoziationen und Differentialdiagnosen zu anaplastisches Oligodendrogliom:
Oligodendrogliom
 
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