A previously healthy 36-year-old woman died suddenly, and autopsy examination disclosed dissection of the left anterior descending coronary artery with luminal occlusion. A periadventitial inflammatory infiltrate consisting predominantly of eosinophils and including histiocytic multinucleated giant cells was present. The syndrome of spontaneous coronary artery dissection is a rare but well-described clinicopathologic entity. The pathogenesis and, specifically, the significance of the periarterial inflammation, has been controversial. The findings in our case, as well as in others reported in the literature, suggest a primarily mechanical process inciting a localized inflammatory reaction, rather than a primary vasculitis.