Recurrent pancreatic arteritis and vasculogenic relapsing pancreatitis in rheumatoid arthritis - a retrospective clinicopathologic and immunohistochemical study of 161 autopsy patients.

The aim of this study was to determine: the prevalence, and histological characteristics of vasculitis in the pancreas, and to follow the formal pathogenesis of multifocal pancreatitis due to arteritis and/or arteriolitis (multifocal vasculogenic pancreatitis). A randomized autopsy population of 161 in-patients with rheumatoid arthritis (RA) was studied. Systemic vasculitis (SV) complicated RA in 36 (22.36%) of 161 cases; tissue samples of pancreas were available for histologic evaluation in 28 patients. Pancreatitis and vasculitis were characterized histologically and immunohistochemically. Vasculogenic, multifocal pancreatitis was not recognized clinically. Vasculitis of the pancreatic arterioles and small arteries (branches of splenic artery, upper and lower gastroduodenal arteries) can lead to local ischaemia and to regressive changes in the pancreas. This vasculogenic process is more or less widespread and multifocal, depending on the number of involved vessels and is followed by reactive inflammation, depending on the stages of the pathological process. Because of the recurrent nature of vasculitis with time these regressive changes accumulate within the pancreas and may contribute to an unexpected circulatory failure and sudden death of the patient. Vasculogenic microinfarcts in the pancreas may be clinically characterized by unexplained recurrent abdominal symptoms and spontaneous remissions which insidiously may lead to metabolic failure resistant to therapy.