PMC7591552_01
(A) Coronal T2 weighted MR abdomen examination showing a pancreatic head ductal lesion (red arrow). (B) Axial T2 weighted MR and (C) axial contrast enhanced CT abdomen showing normal pancreatic body and tail.
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Postoperatively, he continued to have episodes of pancreatitis which prompted an MRCP that demonstrated dilation of the common bile duct and pancreatic duct to 8 mm and 4 mm respectively (Fig. 1A) with a normal pancreatic body and tail (Fig. 1B). CT scan of his chest, abdomen, and pelvis revealed no additional pancreatic lesions (Fig. 1C) or evidence of metastasis.
(A) Partial pancreatoduodenectomy specimen; white arrow denotes ampullary adenoma. (B) Ampullary adenoma with high-grade dysplasia; peri-ampullary glands at left lower. Intraductal tubulopapillary neoplasm with microinvasion (white arrow) at (C) low and (D) high power.
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Following a negative diagnostic laparoscopy, a pancreaticoduodenectomy was performed by a faculty surgeon (Fig. 2A). The first was a 17 x 11 x 8 mm ampullary adenoma with predominantly intestinal morphology and high-grade dysplasia but no evidence of invasion (Fig. 2B). The second lesion, not grossly evident, was characterized by an intraductal proliferation with mixed tubular and papillary architecture, comprised of non-mucinous epithelial cells with variable cytologic atypia, consistent with an intraductal tubulopapillary neoplasm (ITPN; Fig. 2C). Multifocal microinvasion (<2 mm in greatest contiguous dimension) was associated with the ITPN (Fig. 2C and D) but did not extend to the pancreatic neck margin.
(A) Axial T2 weighted MR abdomen showing enlargement of the pancreatic body and tail with multiple new cystic lesions 8 months post-operative from the index operation. (B) Axial post-contrast MR abdomen at 11 months post-operative from the index operation and (C) axial contrast enhanced CT abdomen showing heterogeneous contrast enhancement of the body and tail at 15 months post-operative from the index operation.
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Eight months after his index operation, however, an MRCP was performed that demonstrated multicystic appearance throughout the gland with a dominant pancreatic body cystic lesion measuring 2.6 cm with enhancing mural nodularity, felt to represent either pancreatitis with developing pseudocysts or possibly evolving malignancy (Fig. 3A). Three months later, he underwent repeat MRCP which demonstrated progression of the previously noted multicystic appearance of the remnant pancreas with diffusion restriction on delayed imaging (Fig. 3B). PancraGEN analysis classified the cyst as statistically high risk based on low clonality KRAS point mutation and multiple loss of heterozygosity (LOH) mutations. Preoperative staging CT scan demonstrated known heterogeneous contrast enhancement of the body and tail of the pancreas (Fig. 3C) without evidence of metastatic disease.
(A) Cut section of completion pancreatectomy with intraductal growth of tumor (white arrows). (B) Confluent growth of adenocarcinoma invading transmurally into the lumen of the small intestine (normal small intestine in upper half), and (C) through muscularis propria of small intestinal wall with stromal reaction (residual muscularis propria in lower right). (D) The background pancreas demonstrated diffuse involvement of the duct system by ITPN.
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Serial sectioning of the specimen demonstrated diffuse heterogeneity of the remnant gland with evident distension of residual duct spaces with tumor (Fig. 4A). Histologic examination of the junction between small intestine and pancreas demonstrated confluent growth of a tubulopapillary proliferation with associated stromal reaction consistent with invasive adenocarcinoma, transmurally involving the small intestinal wall (Fig. 4B and C). The background pancreas was remarkable for diffuse involvement of the duct system by ITPN (Fig. 4D).