High-grade and Invasive Intraductal Papillary Mucinous Neoplasm of the Pancreas with STK11 Aberration Having Undergone Pancreatic Resection Three Times for Metachronous Intrapancreatic Recurrences: A Case Report and Review of the Literature.

A 56-year-old woman with high-grade or invasive intraductal papillary mucinous neoplasm (IPMN) underwent 3 pancreatic surgeries for initial and recurrent IPMN lesions. Immunostaining and genetic analyses of all lesions revealed a consistent mutation in KRAS and loss of serine/threonine kinase 11 (STK11), indicating the same origin of these lesions and the possibility of intraductal dissemination. Other immunostaining findings, such as mucin expression and a high Ki-67 labeling index, were consistent among all the lesions and supported their malignant potential. IPMNs with loss of STK11 may benefit from tailored follow-up of the remnant pancreas due to their high likelihood of recurrence through intraductal spread.