Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis Developing Pancreatic Lesion and Diabetes Mellitus: A Case Report and Review of the Literature.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) affects small blood vessels and causes severe systemic organ injury commonly affecting the lungs and kidney. However, gastrointestinal, especially pancreatic, lesions are rare. We report the case of a 67-year-old Japanese man diagnosed with myeloperoxidase (MPO) AAV who developed pancreatic lesions and diabetes mellitus. The patient was admitted to our hospital due to fever, cough, and weight loss. He developed progressive glomerulonephritis, lung nodules, and pancreatic swelling and mass. Additionally, laboratory examination revealed positive MPO-ANCA and elevated glycated hemoglobin A1c, which were suggestive of diabetes mellitus. Renal biopsy revealed necrotizing crescentic glomerulonephritis and vasculitis in the small arteries. Endoscopic ultrasound-guided fine needle aspiration of the pancreas was performed, and histological findings suggested the possibility of pancreatic vasculitis and parenchymal injury. The patient was diagnosed with AAV, which was managed with glucocorticoids. This improved the renal function and pancreatic lesions. Furthermore, blood glucose levels improved despite treatment with glucocorticoids. These findings suggest that AAV-related pancreatic lesions worsened glycemic control. However, glucocorticoid therapy improved vasculitis and pancreatic lesions, which resulted in improved glycemic control.