Vasculitis carcinomatosa occurring in association with adenocarcinoma of the stomach.

Invasion of vascular walls by cancer cells is a well-known phenomenon in lymphoid malignancies. However, its occurrence in epithelial tumors is less well known. This report documents the occurrence of such invasion of vascular walls by an adenocarcinoma of the stomach in a 68-year-old woman. This rare event differs histopathologically from inflammatory vasculitis associated with malignant disease, lymphangitis carcinomatosa, and carcinomatous arteriopathy. In inflammatory vasculitis associated with malignant disease, the main histopathologic feature is fibrinoid necrosis and ordinary pan arteritis-like vasculitis. In lymphangitis carcinomatosa, the main feature is plugging of vascular lumina by tumor cells, a finding not encountered in our case, while in carcinomatosa arteriopathy, the main event is an obliterative fibrointimal hyperplasia, apparently resulting from arterial tumor emboli. In none of these three conditions has direct invasion of vascular walls by tumor cells been previously reported.