The Radiological Mimicry of Ring-Enhancing Lesions: Cerebral Toxoplasmosis Masquerading as Metastatic Disease

A 42-year-old man presented with progressive confusion and was found to have multiple intracranial lesions with surrounding vasogenic oedema on non-contrast computed tomography (CT), initially raising suspicion for metastatic brain disease. Subsequent contrast-enhanced magnetic resonance imaging (MRI) revealed multiple ring-enhancing lesions, indicating the consideration of alternative diagnoses, particularly opportunistic infections. Further workup confirmed undiagnosed HIV/AIDS with severe immunosuppression and positive Toxoplasma gondii serology. A diagnosis of cerebral toxoplasmosis was made. The patient demonstrated significant clinical and radiological improvement following appropriate antiparasitic therapy. This case illustrates the pivotal role of radiologist's insights with neuroimaging in guiding differential diagnosis. It enabled early distinction between neoplastic and infectious etiologies and ultimately directed life-saving treatment in patients with atypical intracranial lesions.