Case Report: Metachronous oncocytic and colloid carcinoma arising from pancreatic intraductal neoplasms over four decades

Résumé fourni par la source

Intraductal papillary mucinous neoplasms (IPMN) are precursors of pancreatic ductal adenocarcinoma (PDAC) and may progress to distinct invasive phenotypes depending on epithelial subtypes. Tubular carcinoma, often arising from pancreatobiliary epithelium, is clinically aggressive and resembles PDAC, whereas colloid carcinoma, typically derived from intestinal epithelium, has a more indolent course. Intraductal oncocytic papillary neoplasms (IOPN), historically considered a subtype of IPMN, are now recognized as a distinct entity characterized by abundant eosinophilic cytoplasm, complex papillary architecture, and unique molecular alterations. Although the heterogeneity of intraductal pancreatic neoplasms (i.e., IPMN, IOPN, ITPN) is recognized, the mechanisms and temporal dynamics underlying their malignant progression remain poorly understood. We report the case of a female patient in her 80s with a pancreatic body cyst first identified in her 40s. After decades of radiologic stability, she underwent a middle pancreatectomy in 2017, which showed a 1.5 cm oncocytic carcinoma (pT1N0) arising from an IOPN. After surgical resection, she remained disease-free for eight years. In 2025, she developed a new pancreatic head cyst and underwent pancreaticoduodenectomy, which revealed a colloid carcinoma (pT3N0) arising from an intestinal-type IPMN. Molecular profiling of the 2025 specimen demonstrated shared driver alterations in the intestinal-type IPMN and associated colloid carcinoma ( KRAS p.G12V and GNAS p.R201C), with BRAF p.D594Y detected in the IPMN component and MTAP deletion detected in the invasive component. Sequencing of the 2017 specimen was not feasible due to limitations of archival tissue. This case describes the metachronous clinical presentation and histologic diagnosis of oncocytic and colloid carcinomas eight years apart within a clinical history spanning nearly four decades. Because sequencing of the 2017 tumor was unsuccessful, clonal independence cannot be established. The case supports prolonged surveillance and further molecular study.

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