Multiple penetrating colonic ulcers in secondary amyloidosis caused by rheumatoid arthritis.

An autopsy case of multiple penetrated colonic ulcers with secondary amyloidosis caused by rheumatoid arthritis in a 61 year old woman is reported. Amyloid deposition was conspicuous in the transverse colon with numerous penetrating ulcers that were circumferentially scattered. Deposition was mainly in the small vessel walls of the submucosal layers. In the quantitative comparison of the histological components between the colonic segments affected by severe and mild ulcer formation, occlusive vascular amyloid deposition was revealed more frequently in the severe involved portion than in the mild involved portion. In addition, submucosal fibrosis that tended to appear around ulcers was more extensive and thicker in the former than in the latter. The complete vascular occlusion caused by amyloid deposition was particularly concentrated in the submucosal layer adjacent to the ulcer. These findings indicate that peripheral circulatory disturbance by amyloid deposition in the small vascular walls leads to ulcer formation in the colon.