Diagnostic challenges of a giant cerebral cavernous malformation mimicking a glioma in a 16-year-old male

Background: Giant cavernous malformation (GCM) is an exceptionally rare atypical form of cerebral cavernous malformations (CCMs) that poses significant diagnostic challenges due to its ill-defined margins and heterogeneous appearance, which may closely mimic primary brain tumors, particularly low-grade gliomas. Case Description: We report the case of a 16-year-old male who presented with generalized seizures and was found to have a large lesion in the left temporo-occipital region, predominantly involving the mediobasal temporal lobe. Magnetic resonance imaging revealed a heterogeneous “salt-and-pepper” appearance with ill-defined margins. Computed tomography demonstrated focal calcification, with an initial impression favoring oligodendroglioma. The patient underwent surgical resection, and histopathological analysis confirmed the diagnosis of a GCM. Conclusion: Giant CCM should be considered in the differential diagnosis of atypical hemorrhagic brain lesions with aggressive imaging features. Histopathology remains the gold standard for diagnosis, and this case contributes additional evidence to the sparse literature on this uncommon presentation.