A 28-year-old woman presents with acute onset of right-sided visual blurring and left leg weakness that partially resolves over weeks. MRI shows multiple periventricular white matter lesions perpendicular to the ventricles (Dawson's fingers). Histology of a brain biopsy would show which characteristic finding?

• A Sharply demyelinated plaques with relative axonal preservation and perivascular lymphocytic infiltrate ✓
• B Perivascular amyloid deposition with birefringent Congo red staining
• C Spongiform change with extensive neuronal loss and astrogliosis
• D Eosinophilic intracytoplasmic Negri bodies in hippocampal neurons

Explanation

Multiple sclerosis is characterized by sharply demyelinated plaques with relative preservation of axons, perivascular chronic inflammation (lymphocytes and macrophages), and reactive astrogliosis. Dawson's fingers (periventricular ovoid lesions radiating perpendicular to ventricles) are classic on MRI. Amyloid angiopathy shows Congo red-positive vessels. Spongiform change is seen in prion diseases. Negri bodies are seen in rabies.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.