Multifocal High-Grade Pancreatic Precursor Lesions: A Case Series and Management Recommendations

Background: The risk of developing invasive cancer in the remnant pancreas after resection of multifocal high-grade pancreatic precursor lesions is not well known. We report three patients who were followed up after resection of multifocal high-grade pancreatic intraepithelial neoplasia (PanIN)-3 or intraductal papillary mucinous neoplasia (IPMN), two of whom eventually developed invasive carcinoma.

Presentation: 1) 68-year-old woman who had a laparoscopic distal pancreatectomy for multifocal mixed-type IPMN, identified as high-grade on final pathology, with negative surgical margins. During semiannual monitoring, eight years from the first surgery, the patient developed suspicious features prompting surgical resection of the body with final pathology revealing invasive ductal adenocarcinoma in the setting of IPMN. 2) 48-year-old woman who had a distal pancreatectomy for severe acute/chronic symptomatic pancreatitis, with final pathology revealing multifocal high-grade PanIN-3, with negative surgical margins. Despite semiannual monitoring, two years from the first surgery, the patient developed pancreatic adenocarcinoma with liver metastasis. 3) 55-year-old woman who had a Whipple procedure for symptomatic chronic pancreatitis, with multifocal PanIN-3 on final pathology. The patient underwent completion pancreatectomy due to symptomatology and her high-risk profile, with final pathology confirming multifocal PanIN-3.

Conclusion: Multifocal high-grade dysplastic lesions of the pancreas might benefit from surgical resection.

Risk of Neoplastic Progression in Individuals at High Risk for Pancreatic Cancer Undergoing Long-term Surveillance

BACKGROUND & AIMS

Screening of individuals who have a high risk of pancreatic ductal adenocarcinoma (PDAC), because of genetic factors, frequently leads to identification of pancreatic lesions. We investigated the incidence of PDAC and risk factors for neoplastic progression in individuals at high risk for PDAC enrolled in a long-term screening study.

METHODS

We analyzed data from 354 individuals at high risk for PDAC (based on genetic factors of family history), enrolled in Cancer of the Pancreas Screening cohort studies at tertiary care academic centers from 1998 through 2014 (median follow-up time, 5.6 years). All subjects were evaluated at study entry (baseline) by endoscopic ultrasonography and underwent surveillance with endoscopic ultrasonography, magnetic resonance imaging, and/or computed tomography. The primary endpoint was the cumulative incidence of PDAC, pancreatic intraepithelial neoplasia grade 3, or intraductal papillary mucinous neoplasm with high-grade dysplasia (HGD) after baseline. We performed multivariate Cox regression and Kaplan-Meier analyses.

RESULTS

During the follow-up period, pancreatic lesions with worrisome features (solid mass, multiple cysts, cyst size > 3 cm, thickened/enhancing walls, mural nodule, dilated main pancreatic duct > 5 mm, or abrupt change in duct caliber) or rapid cyst growth (>4 mm/year) were detected in 68 patients (19%). Overall, 24 of 354 patients (7%) had neoplastic progression (14 PDACs and 10 HGDs) over a 16-year period; the rate of progression was 1.6%/year, and 93% had detectable lesions with worrisome features before diagnosis of the PDAC or HGD. Nine of the 10 PDACs detected during routine surveillance were resectable; a significantly higher proportion of patients with resectable PDACs survived 3 years (85%) compared with the 4 subjects with symptomatic, unresectable PDACs (25%), which developed outside surveillance (log rank P < .0001). Neoplastic progression occurred at a median age of 67 years; the median time from baseline screening until PDAC diagnosis was 4.8 years (interquartile range, 1.6-6.9 years).

CONCLUSIONS

In a long-term (16-year) follow-up study of individuals at high-risk for PDAC, we found most PDACs detected during surveillance (9/10) to be resectable, and 85% of these patients survived for 3 years. We identified radiologic features associated with neoplastic progression.

Immature squamous metaplasia (focal atypical epithelial hyperplasia) of the pancreatic duct-immunohistochemical distinction from intraductal carcinoma

AIMS

Immature squamous metaplasia of the pancreatic duct (ISMPD) can be difficult to differentiate from an intraductal carcinoma of the pancreas (ICP), and little is known about the pathological nature of ISMPD. The aim of this study was to analyse 20 ISMPD and 10 ICP tissue samples.

METHODS AND RESULTS

ISMPD shares some characteristics with ICP. Seven of 20 ISMPD samples were covered by a layer of pancreatic duct epithelium, whereas this was not seen in the ICP samples. Immunohistochemistry of ISMPD revealed positivity for p63 (100%), cytokeratin 5/6 (95%), cytokeratin 7 (95%), cytokeratin 20 (10%), and MUC-1 (95%), and the samples were negative for p53, carcinoembryonic antigen (CEA), and bcl-2. In contrast, ICP was positive for p63 (40%), p53 (10%), cytokeratin 7 (90%), cytokeratin 20 (20%), CEA (30%), and MUC-1 (80%), and negative for cytokeratin 5/6. However, in 84% (16) of the ISMPD samples, cytokeratin 7 was expressed only by an epithelial layer at the apical surface; this expression pattern was not found in any of the 10 ICP samples. The mean Ki67 labelling index was 1.0% in ISMPD and 18.5% in ICP.

CONCLUSIONS

Our study suggests that immunohistochemical staining for cytokeratin 5/6 and Ki67 constitutes the best combination for differentiating ISMPD from ICP.

Pancreatic intraepithelial neoplasia-3 with localized acute pancreatitis in the main pancreatic duct

Pancreatic intraepithelial neoplasia (PanIN) is one of the most important issues for the early detection of pancreatic ductal adenocarcinoma. In particular, PanIN-3 is recognized as a precancerous lesion, e.g., carcinoma in situ, high-grade dysplasia, and severe dysplasia. We report a rare, completely resected case of PanIN-3 in the main pancreatic duct (MPD) detected from localized pancreatitis. A 63-year-old man developed upper abdominal pain with hyperamylasemia. He underwent distal pancreatectomy soon after recovery because an abnormal narrow segment, suggesting PanIN, was identified in the pancreatic body by endoscopic retrograde cholangiopancreatography. Histopathological findings revealed a PanIN-3 located in the MPD that could be resected completely. This finding suggests that if unidentified localized pancreatitis develops, we should carefully examine the fine structural changes in the MPD.

Microinvasion of high-grade pancreatic intraepithelial neoplasia

High-grade pancreatic intraepithelial neoplasia (PanIN-3) is recognized as a precursor lesion of invasive ductal carcinoma (IDC). However, histological evidence that PanIN-3 invades beyond the basement membrane of pancreatic ductal epithelium, that is, the moment PanIN-3 becomes IDC, has not been captured yet. This may be because PanINs which are microscopic papillary or flat lesion rarely develop clinical symptoms and are not detectable on imaging examination. On the other hand, most IDCs were found in the advanced stage with massive invasion. In this report, PanIN-3 obstructed several branch pancreatic ducts and subsequently caused pancreatitis which developed clinical symptom and was detectable as a pancreatic mass in imaging studies. A 65-year-old woman was referred to our institution for further examination of her repeated pancreatitis. Abdominal ultrasound revealed a low echoic mass of 13 mm in diameter in the pancreatic body without upstream dilatation of the main pancreatic duct (MPD). Endoscopic retrograde pancreatography showed a strictured segment of 2 mm in length in the MPD at the pancreatic body. Cytological examination of pancreatic juice revealed adenocarcinoma and distal pancreatectomy was performed. A resected specimen revealed a whitish mass of 15 mm in diameter in the pancreatic body, which was identified as pancreatitis by histological examination. Papillary growth of PanIN-3 was seen mainly in the branch ducts. Each PanIN-3 was located separately in the branch ducts with normal epithelia in the MPD between them. In three adjacent branch ducts, PanIN-3 was observed to be invading microscopically beyond the basement membrane.