Presentation
Seizures.
Patient Data
Large intra-axial right frontal mass expanding the cortex and subcortical white matter and extending to the insular region with effacement of the cerebral sulci and a mass effect on the frontal horn. It displays an isosignal to the cortical grey matter on T1, high signal on T2 and FLAIR peripherally with areas high signal on T1, low signal on T2 with a signal loss on GE sequence (calcifications). The central area appears of low signal on T1 and FLAIR and high signal on T2 with no restricted diffusion (cystic changes). The postcontrast sequences show mild enhancement of the peripheral solid component.
Small lesion within the substance of the splenium of the corpus callosum of low signal on T1, high signal on T2/FLAIR with restricted diffusion and no enhancement on postcontrast sequences suggestive of a cytotoxic lesion of the corpus callosum (CLOCCs).
Small vessel ischemic changes are noted.
An area of cortical laminar necrosis is noted in the right occipital region.
Left parietal extra-axial cystic structure, probably arachnoid cyst.
Case Discussion
MRI features of a large intra-axial tumor of the right frontal lobe expanding the cortex and subcortical white matter with foci of calcification and central cystic degeneration, suggestive of an oligodendroglioma.
General imaging differential considerations include:
-
astrocytoma:
- more common
- T2/FLAIR mismatch sign
- usually well-defined margins
- calcification strongly favors oligodendroglioma
-
ganglioglioma
- calcifications less common than oligodendroglioma
-
pleomorphic xanthoastrocytoma (PXA)
- calcifications are rare
- CAPNON: entirely calcified