Intraductal Papillary Mucinous Neoplasm with Pancreatogastric Fistula

Abstract

We herein report a rare case of intraductal papillary mucinous neoplasm with a pancreatogastric fistula in an elderly Japanese man admitted to our hospital. The pancreatogastric fistula was confirmed using endoscopic retrograde pancreatography via a cannulated guidewire placed in the stomach. Six months after admission, the patient was diagnosed with intraductal papillary mucinous carcinoma. A pancreatogastric fistula is generally a rare complication of intraductal papillary mucinous neoplasm. It was caused by mechanical penetration in this case. Interestingly, we also observed endoscopic and histochemical mucosal changes in the fistula.

Keywords: endoscopic retrograde cholangiopancreatography; intraductal papillary mucinous carcinoma; intraductal papillary mucinous neoplasm; mechanical penetration; pancreatogastric fistula.

Figure 1.

Findings of diagnostic imaging. A: Esophagogastroduodenoscopy showing the papillary tumor with a typical fish egg-like mucosal lesion on the fistula. B: Abdominal enhanced computed tomography showing a cystic lesion of the pancreas and pancreatogastric fistula. C: Endoscopic ultrasonography confirming a pancreatogastric fistula.

Figure 2.

A pathological examination of the initial biopsy specimen. A: Hematoxylin and Eosin staining: low-power microscopy showing a non-invasive intraductal papillary mucinous neoplasm border with the fistula in the stomach. B, C: Immunohistochemical staining revealing that around 30% neoplastic cells were Ki-67-positive (B), and the majority were p53-negative (C).

Figure 3.

Findings of endoscopic retrograde cholangiopancreatography. A: Endoscopic retrograde cholangiopancreatography showing the main pancreatic duct and pancreatogastric fistula. A guidewire was inserted into the stomach via the pancreatogastric fistula. B: Endoscopically confirmed guidewire placement in the stomach.

Figure 4.

Follow-up imaging findings. A: Abdominal computed tomography showing gradual enlargement of the pancreatogastric fistula and pancreatic cystic lesion during follow-up. In addition, there were several metastatic lesions in the liver along with dilatation of the intrahepatic bile duct. B: Compared with the previous esophagogastroduodenoscopy findings, the mucous membrane was irregular, and the fish egg-like appearance of the fistula had disappeared.

Figure 5.

A pathological examination of the second biopsy specimen. A: Hematoxylin and Eosin staining: high-power microscopy showing an invasive intraductal papillary mucinous carcinoma with a fistula in the stomach. B: Immunohistochemically, around 70% of the neoplastic cells showed Ki-67 expression. C: Immunohistochemically, around 40% of the neoplastic cells showed p53 expression.