Autoimmune Pancreatitis Accompanied by Tubulointerstitial Nephritis

Lee, Yu Hwa; Tae, Hye Jin; Kim, Jin Ok; Choi, Jeong Im; Kim, Dong Chan; Sohn, Won; Choi, Ho Soon

Abstract

Autoimmune pancreatitis (AIP) is type of chronic pancreatitis characterized by an autoimmune inflammatory process. IgG4-positive plasma cells can be found in both the pancreas and at extrapancreatic sites of involvement. A 60-year-old man presented with abdominal discomfort. Computed tomography revealed enlargement of the pancreas and kidneys as well as low-attenuated lesions in both kidneys. MRCP showed narrowing of the distal common bile duct and the proximal pancreatic duct. The serum IgG level was elevated, but IgG4 was normal. Histologic examination revealed lymphoplasma infiltration in the renal tubulointerstitium associated with fibrosis along with many IgG4-positive plasma cells, thereby confirming the diagnosis of tubulointerstitial nephritis-associated AIP. The abnormalities in the clinical, laboratory, and radiological findings improved after oral steroid treatment. This is a case of autoimmune pancreatitis accompanied by tubulointerstitial nephritis diagnosed by renal biopsy. Clinicians should suspect the possibility of extrapancreatic organ involvement in autoimmune pancreatitis, especially when abnormalities in other organs are suggested. Proper examinations must be performed.