A 50-year-old immunocompetent patient presents with a ring-enhancing lesion in the temporal lobe on MRI. CSF shows lymphocytic pleocytosis, elevated protein, normal glucose. PCR for herpes simplex virus is positive. The pathological hallmark on brain biopsy would be:

• A Microglial nodules with neuronophagia
• B Cowdry type A intranuclear inclusion bodies in neurons and glia ✓
• C Caseating granulomas with Langhans giant cells
• D PAS-positive capsulate yeast forms in perivascular spaces

Explanation

HSV encephalitis characteristically involves the temporal and orbitofrontal lobes. Histologically, infected neurons and glial cells show Cowdry type A intranuclear inclusion bodies—eosinophilic inclusions surrounded by a halo—along with perivascular lymphocytes and hemorrhagic necrosis. Microglial nodules with neuronophagia are seen in other viral encephalitides; caseating granulomas characterize tuberculous meningitis; PAS-positive capsulate yeast (Cryptococcus) in perivascular spaces is seen in cryptococcal meningitis.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.