Introduction <p>White matter hyperintensities on magnetic resonance imaging are a frequent finding. Anaplastic astrocytoma as a cause of persistent, symmetrical white matter hyperintensities is unusual.</p> Case presentation <p>A 22-year-old Sri Lankan male presented with an episodic, nonspecific headache for 1&#xa0;month’s duration, which was followed by brief episodes of altered awareness and a progressive decrease in consciousness. The physical examination showed a reduced conscious state without any focal neurological signs. Non-contrast computed tomography brain showed cerebral edema and dilated temporal horns of the lateral ventricles. Magnetic resonance imaging of the brain showed extensive, symmetrical T2 and fluid-attenuated inversion recovery hyperintensities involving the corpus callosum, pericallosal region, periventricular white matter, deep white matter, and bilateral cerebellar hemispheres surrounding the dentate nuclei, without diffusion restriction or contrast enhancement. In addition, the body of the lateral ventricles were compressed leading to dilatation of the temporal horns. The cerebrospinal fluid full report was normal, and the cerebrospinal fluid cultures and cytology was negative. External ventricular drainage was placed after consultation with the neurosurgeons. He was treated with intravenous 3% sodium chloride for a few days and intravenous dexamethasone, intravenous ceftriaxone, and intravenous acyclovir for 14&#xa0;days. There was no significant clinical or radiological improvement. A ventricular wall biopsy was performed. This showed an anaplastic astrocytoma (World Health Organization Grade III). The patient was subsequently referred for specialized oncological management, but&#xa0;died&#xa0;following the initiation of chemotherapy.</p> Conclusion <p>This case highlights the unusual presentation of a primary central nervous system tumor with symmetrical, persistent white matter hyperintensities.</p>