Histopathology of<unk>  types in a distal pancreatectomy specimen from a 60-year-old man, by gross pathology (center image), microscopy and immunohistochemistry: The resected specimen (c) revealed that the mural nodule in the MPD consisted of PB-type<unk>  with high-grade dysplasia (adenocarcinoma) (a) with a diffuse positivity of p53 immunostaining (an insert) and KRAS mutation (G12V). The BD-IPMN of the body was lined by gastric mucinous epithelium showing low<unk>  configuration with mild epithelial stratification with the same KRAS mutation (d), and the proliferation of similar gastric<unk>  components sequentially involved the bottom of the mural nodule and the wall of the surrounding dilated MPD (indicated by red arrowheads) (b). The BD-IPMN of the tail was lined by flat, monolayer gastric mucinous epithelium lacking cellular atypia and KRAS mutation (e). In most cases,<unk> s are diagnosed based on clinical and radiographic criteria. If fluid from the cyst is aspirated, the CEA level is typically elevated. Confirmation of the diagnosis with tissue is rarely necessary. By histopathology,<unk>  is characterized on light microscopy by Mucinous epithelial cells, and growth within the pancreatic ducts. Mucin 5AC is a useful immunohistochemistry marker. Characteristic genetic alterations are those of KRAS and GNAS. Further subtyping of<unk>  can be done as either: *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 duct greater 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.
Intraductal papillary mucinous neoplasm
Pancreatic mucinous cystic neoplasm
Pancreatic serous cystadenoma
Pancreatic pseudocyst
Bile duct hamartoma
Pancreatic mucinous cystadenoma
Collecting duct carcinoma
Phyllodes tumor