True or false: Dense transmural inflammatory infiltrates are seen in Kawasaki disease and PAN.

True or false: Dense transmural inflammatory infiltrates are seen in Kawasaki disease and PAN.

• A. True
• B. False
• C. Both show granulomatous inflammation
• D. Neither shows transmural infiltration

Answer: (A)

Dense transmural inflammatory infiltrates mean inflammation spanning the entire vessel wall, a pattern seen in certain medium-sized vessel vasculitides. In Kawasaki disease, the acute vasculitis often involves the coronary and other medium-sized arteries with panarteritis, where inflammatory cells can fill the wall from intima through adventitia, producing transmural involvement and even necrotizing arteritis in the acute phase. In polyarteritis nodosa, the classic lesion is a transmural necrotizing inflammation of medium-sized arteries with a dense inflammatory infiltrate across all layers, often accompanied by fibrinoid necrosis. Because both diseases can exhibit inflammation that traverses the full thickness of the vessel wall, the statement is true.

Dense transmural inflammatory infiltrates mean inflammation spanning the entire vessel wall, a pattern seen in certain medium-sized vessel vasculitides. In Kawasaki disease, the acute vasculitis often involves the coronary and other medium-sized arteries with panarteritis, where inflammatory cells can fill the wall from intima through adventitia, producing transmural involvement and even necrotizing arteritis in the acute phase. In polyarteritis nodosa, the classic lesion is a transmural necrotizing inflammation of medium-sized arteries with a dense inflammatory infiltrate across all layers, often accompanied by fibrinoid necrosis. Because both diseases can exhibit inflammation that traverses the full thickness of the vessel wall, the statement is true.