case_images: PMC11793926_01
case_images: Radiological images before treatment. A space-occupying lesion within the right lateral ventricle is observed on computed tomography (CT) and magnetic resonance imaging (MRI) axial images. The sagittal section of the T1-weighted image (T1WI) suggests that the tumor has arisen from the subcallosal gyrus, extending to the anterior cingulate gyrus and putamen. T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequences show a typical "T2-FLAIR mismatch sign." Quantitative magnetic resonance (MR) relaxometry suggests the tumor to be an astrocytoma, isocitrate dehydrogenase (IDH)-mutant. The region of interest (ROI) crafted on FLAIR was placed at the tumor lesion on both T1 and T2 images. The red ROI indicates the entire lesion, while the orange ROI indicates the T2-FLAIR mismatch region.
case_images: cureus-0017-00000076963-i01.jpg
case_images: PMC11793926_01_cureus-0017-00000076963-i01.jpg
case_images: FIG1
case_images: Despite its unusual anatomical location, qualitative and quantitative imaging features strongly suggested an IDH-mutant astrocytoma arising from the subcallosal gyrus (Figure 1).
case_images: Radiological images after surgery accompanied by pathological images. Seventy percent of the tumor volume was resected via the trans-superior frontal gyrus route with improved hydrocephalus. Hematoxylin and eosin (HE) staining showed diffuse proliferation of atypical astrocytic cells, and IDH1 R132H immunohistochemistry (ICH) confirmed IDH1 mutation. Pathological photographs are taken at 20x magnification. The final diagnosis was astrocytoma, IDH-mutant, CNS WHO grade 3.
case_images: cureus-0017-00000076963-i02.jpg
case_images: PMC11793926_01_cureus-0017-00000076963-i02.jpg
case_images: FIG2
case_images: The patient is scheduled to undergo a second surgery aiming for an extent of resection greater than 90%, as it has been discussed that the extent of resection could have a significant prognostic impact on astrocytoma, IDH-mutant, CNS WHO grade 3 (Figure 2).