The MOST reliable indicator of healed rheumatic myocarditis on histology is:

• A Diffuse lymphocytic infiltration of the myocardium
• B Eosinophil-rich infiltrate around the coronary arteries
• C Aschoff nodules — plump macrophages (Aschoff/Anitschkow cells) around fibrinoid necrosis ✓
• D Hyaline thickening of intramyocardial arterioles

Explanation

Aschoff nodules are pathognomonic of rheumatic carditis, consisting of a central zone of fibrinoid necrosis surrounded by Aschoff cells (activated macrophages with 'caterpillar' or owl-eye nuclei, also called Anitschkow cells) and lymphocytes. In healed rheumatic disease, fibrosed Aschoff nodules persist as a marker of prior inflammation. Diffuse lymphocytic infiltration is nonspecific; eosinophilic infiltrates suggest hypersensitivity myocarditis.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.