Concomitant Pancreatic Ductal Adenocarcinoma and Type 1 Autoimmune Pancreatitis: A Potential Issue in the Diagnosis of Carcinoma by Endoscopic Ultrasound-guided Fine-needle Biopsy

Abstract

We herein report a 64-year-old man with concomitant pancreatic ductal adenocarcinoma (PDAC) and type 1 autoimmune pancreatitis (AIP). An endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) from the pancreatic head mass revealed level 2 histology of AIP and atypical glands. We diagnosed definitive focal AIP using the clinical diagnostic criteria. Computed tomography revealed that the pancreatic mass had not been reduced by steroid therapy. Surgery was performed after a histological PDAC diagnosis was made via a transpapillary biliary biopsy. The resected specimen revealed PDAC associated with AIP. It is important to consider the cooccurrence of PDAC and AIP even if the histological diagnosis via an EUS-FNB is AIP.

Keywords: autoimmune pancreatitis; endoscopic ultrasound-guided fine-needle biopsy; pancreatic ductal adenocarcinoma; steroid pulse therapy.

Figure 1.

The pancreatic head mass was hypovascular in the pancreatic phase and enhanced in the portal and delayed phases on contrast-enhanced CT (A: pancreatic phase, B: portal phase, C: delayed phase).

Figure 2.

A: Dense lymphoplasmacytic infiltration and fibrosis were observed [Hematoxylin and Eosin (H&E) staining, ×10 objective]. B: Numerous IgG4-positive cells were identified diffusely in the inflamed portions (IgG4 ×20 objective). C, D: Some atypical glands (arrows) were identified (H&E staining, C: ×20 objective, D: ×40 objective).

Figure 3.

A: Endoscopic retrograde pancreatography showed the narrowing of the main pancreatic duct and the duct of Santorini as well as dilation of the branch duct in the head and uncus of the pancreas. B: Endoscopic retrograde cholangiography showed the distal common bile duct stricture.

Figure 4.

The pancreatic head mass had not shrunk in size after the steroid therapy on contrast-enhanced CT (A: pancreatic phase, B: portal phase, C: delayed phase).

Figure 5.

A: The narrowing of the main pancreatic duct and the duct of Santorini were slightly improved on endoscopic retrograde pancreatography. B: The distal common bile duct stricture was slightly improved on endoscopic cholangiography.

Figure 6.

A: Effacement and degeneration of cancer cells by neoadjuvant chemotherapy were markedly observed (Hematoxylin and Eosin staining ×10 objective). B: Substantial obliterative phlebitis consisting of both inflammatory cells and fibrosis (arrows) was noted (EVG ×4 objective). C: A few IgG4-positive cells were observed (IgG4 ×20 objective).

Figure 7.

Clinical course.