A 43-year-old white man with a history of cigarette smoking, hypertension, nephrolithiasis, and cervical degenerative arthritis was hospitalized for sudden-onset, severe, substernal, and pleuritic chest pain with epigastric radiation. Despite evaluation, the cause remained unclear and the patient expired on hospital day 5. Autopsy revealed acute Stanford type A aortic dissection, hemopericardium, and hemothorax. Grossly, the aorta and its branches, including uninvolved medium-sized arteries, displayed extreme mural fragility. Microscopic examination showed a primary lymphoplasmacytic aortitis-periaortitis without giant cells. Rents within the tunica media, medial-adventitial inflammation, and elastic fiber disruption were limited to sites of gross aortic dissection. Muscular arteries showed patchy, chronic arteritis-periarteritis without giant cell infiltrate or aneurysm formation. This case documents an unusual association of primary lymphoplasmacytic aortitis and aortic dissection.