Complete durable response of a pediatric anaplastic oligodendroglioma to temozolomide alone: Case report and review of literature

Abstract

Anaplastic oligodendroglioma (AO) is rare in children. Treatment typically consists of varying combinations of surgery, chemotherapy, and radiotherapy. We present a pediatric case of frontal lobe AO with periventricular subcallosal extension and local leptomeningeal involvement. The isocitrate dehydrogenase (IDH) wild-type tumor was MGMT methylated and contained an ATRX mutation, BRAF alteration, and 1p/19q co-deletion; a combination of alterations mostly encountered in pediatric oligodendrogliomas. The patient underwent a near total resection and had a complete, durable response to temozolomide alone, suggesting that conservative management without radiation may be appropriate in some cases. We review the literature of this uncommon subtype of glioma in children.

Keywords: 1p19q; children; codeletion; oligodendroglioma; pediatric; temozolomide.

FIGURE 1

Magnetic resonance imaging of the brain. (A and B) T2-weighted axial images at diagnosis show a heterogeneous, hyperintense mass in the left inferomedial frontal lobe that extends to the left periventricular subcallosal region. Fluid level in the left occipital horn from hemorrhage (arrow). (C) Precontrast T1 sagittal image at diagnosis shows areas of T1 hyperintensity in the mass and in the left ventricle from hemorrhage. (D) Postcontrast T1 axial image shows enhancement in the solid components of the mass, separate from areas of hemorrhage (arrows). (E) T2 axial image 3-week posttumor resection shows residual hyperintense mass in the splenium of corpus callosum (arrow). (F) T1 axial postcontrast image at 3-week postresection shows enhancement in the residual mass in the genu of corpus callosum (arrow). The enhancement in the margin of the resection cavity and in the pachymeninges is postsurgical reactive change. (G) T2 axial image at most recent follow-up 42 months off therapy shows gliosis in the genu of corpus callosum at the site of residual tumor and around the resection cavity reaching the ventricular margin. (H) Postcontrast T1 axial image at most recent follow-up shows hypointensity in the same area with no solid enhancement. The linear enhancement is in a vein (arrow)

FIGURE 2

Histopathology of pediatric anaplastic oligodendroglioma. Hematoxylin and eosin stain (A–D) as well as immunohistochemistry for GFAP (E) and MIB-1 (F). Microscopic examination demonstrates a glial neoplasm composed of cells having relatively uniform, round nuclei and prominent perinuclear halo (A and B). Occasional mitotic figures (B), focal microvascular proliferation (C), and foci of pseudopalisading necrosis (D) are identified