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INTRODUCTION: Intraductal papillary mucinous neoplasms (IPMN) are cystic lesions of the pancreas that follow a step-wise dysplastic sequence from adenoma to invasive adenocarcinoma. Obtaining a frozen section (FS) at the time of pancreatic resection could be important to determine whether additional resection of the remnant is required. The aim of this study is to report the correlation between FS of the pancreatic neck and final histopathology for patients with IPMN including those with IPMN carcinomas.
METHODS: The departmental pancreatic cyst database was interrogated to identify all patients with a histopathological diagnosis of IPMN with or without pancreatic adenocarcinoma arising from within the IPMN. The degree of dysplasia on the final pathology report was classified as high (HGD), moderate (MGD), or low (LGD. Frozen section results were reviewed with particular reference to identification of invasive carcinoma or high-grade dysplasia and these findings were compared to final histopathological findings, and related to patient outcome.
RESULTS: During the period January 2000 to December 2011, 121 patients underwent resection, consisting of 41 patients with an invasive carcinoma and 80 with IPMN alone: HGD [n=18]; MGD [n=14]; and LGD [n=48] (on final pathology). There were 70 females and 51 males with a median age of 68 years (IQR: 58-73). Of the patients with IPMN carcinomas, 36 (88%) had a FS. Carcinoma or HGD was seen at the transaction margin on FS in 4 patients undergoing pancreatoduodenectomy leading to 4 extended resections, 2 of which were total pancreatectomies. There was 1 false-positive for invasive cancer that was found to be non invasive on final pathology and 1 false-negative for HGD/invasive carcinoma on frozen section that was found to be an invasive cancer on final pathology. For those with IPMN alone, 64 had frozen section analysis performed. None had carcinoma/HGD at the transection margin on FS or on subsequent histopathology. 3 patients in this group died of IPMN-related carcinomas in their remnant pancreas. 2 had HGD on their initial resection and 1 had only LGD, and all developed the subsequent cancers away from the transaction margin.
CONCLUSIONS: Frozen section analysis allows identification of foci of carcinoma or HGD at the transection margin during pancreatic resection for IPMN that should result in further resection. However, the development of progressive disease in the pancreatic remnants of patients without initial evidence of carcinoma means that radiological surveillance is required for this cohort.