Intraductal papillary mucinous neoplasm is a type of tumor that can occur within the cells of the pancreatic duct. IPMN tumors produce mucus, and this mucus can form pancreatic cysts. Although intraductal papillary mucinous neoplasms are benign tumors, they can progress to pancreatic cancer. As such IPMN is viewed as a precancerous condition. Once an intraductal papillary mucinous neoplasm has been found, the management options include close monitoring and pre-emptive surgery.
Gross pathology: Main duct, branch duct, and mixed duct lesions, which determines surgical management. Main duct lesion is the segmental or diffuse dilatation of main pancreatic ductgreater than 5 mm without other causes of obstruction. Meanwhile, branch duct lesion is the pancreatic cyst more than 5 mm that communicates with the main duct. The mixed duct lesions fulfills both criteria above.
By light microscopy and immunohistochemistry: Gastric, intestinal, pancreaticbiliary, and oncocytic.
: The resected specimen revealed that the mural nodule in the MPD consisted of PB-type IPMN with high-grade dysplasia with a diffuse positivity of p53 immunostaining and KRAS mutation. The BD-IPMN of the body was lined by gastric mucinous epithelium showing low papillary configuration with mild epithelial stratification with the same KRAS mutation, and the proliferation of similar gastric IPMN components sequentially involved the bottom of the mural nodule and the wall of the surrounding dilated MPD . The BD-IPMN of the tail was lined by flat, monolayer gastric mucinous epithelium lacking cellular atypia and KRAS mutation.
Treatment
The treatment of choice for main-duct IPMNs is resection due to approximately 50% chance of malignancy. Side-branch IPMNs are occasionally monitored with regular CT or MRIs, but most are eventually resected, with a 30% rate of malignancy in these resected tumors. Survival 5 years after resection of an IPMN without malignancy is approximately 80%, 85% with malignancy but no lymph node spread and 0% with malignancy spreading to lymph nodes. Surgery can include the removal of the head of the pancreas, removal of the body and tail of the pancreas, or rarely removal of the entire pancreas. In selected cases the surgery can be performed using minimally invasive techniques such as laparoscopy or robotic surgery. A study using Surveillance, Epidemiology, and End Result Registry data suggested that increased lymph node counts harvested during the surgery were associated with better survival in invasive IPMN patients.
