A. Biopsy, fine needle aspiration, and brushing cytology specimens may be obtained percutaneously, intraoperatively, or via endoscopic retrograde cholangiopancre-atography (ERCP). Needle core biopsies should be immediately fixed in 10% formalin. The number and the length, or length range, of the biopsies should be recorded. Documentation of the number and length is important to ensure that the biopsies are adequately represented on the slides. Three H&E-stained slides from each block are prepared for microscopic examination. Aspiration smears are processed with alcohol fixation for Papanicolaou staining or air dried for Diff-Quik staining. Brushings are handled by routine liquid-based cytology methods.

B. Distal pancreatectomy specimens consist of the pancreatic tail (usually with attached spleen) and a portion of the pancreatic body. After orientation, each organ should be measured separately. An externally visible mass or lesion should be documented for its size, extent, and location. The proximal and peripancreatic margins should be inked. Before sectioning through the pancreas, the proximal margin is typically taken either as a shave margin or as a series of perpendicular sections, depending on the location of tumor. The method of sectioning the pancreas depends on personal preference. One method is to bivalve the pancreas using a probe in the main duct as a guide; another method is to section the pancreas in a breadloaf fashion. The size and characteristics of any lesions (masses or cysts), along with their relationship to the main duct, spleen, and peripancreatic soft tissue resection margins should be documented. If the
lesion is cystic, the cyst contents and the cysts relationship to the main duct should be also documented.

Sections from the lesion should include samples that demonstrate the relation of the lesion to margins and uninvolved pancreas. If the pancreatic lesion is cystic and small, it should be submitted in its entirety. For large lesions (e.g., >5 cm), at least one section per centimeter is recommended, which should focus on thickened, solid, or irregular areas. One or more perpendicular sections from the inked posterior (retroperitoneal) soft tissue margin should be submitted. One to two representative sections from the spleen are sufficient unless gross abnormalities are detected. Finally, the peripancreatic and splenic hilar soft tissue is searched for lymph nodes; all identified lymph nodes should be submitted in their entirety for microscopic examination.

C. The Whipple procedure, performed for tumors of the pancreatic head, common bile duct, ampullary, or periampullary region, involves excision of a composite specimen usually consisting of the pancreatic head, a portion of the common bile duct, the duodenum, the distal stomach, and the gallbladder. After orientation, the dimension of each organ should be measured. The various surgical margins of the pancreas (pancreatic neck, posterior, portal vein groove, and uncinate) should be inked with different colors in the operating room with the surgeon’s aid; frozen section evaluation of the pancreatic neck and bile duct margins is almost always requested intraoperatively. The stomach is opened along the greater curvature and the duodenum is opened along the aspect opposite the pancreas to avoid the ampulla. The pancreas can be sectioned along the plane defined by the pancreatic duct and bile duct using probes as a guide, or cut perpendicularly. The size, location, and nature of the tumor are recorded, as is the relation of the tumor to the margins. If the tumor is cystic, the cyst contents and the relationship of the cyst to the main duct should be documented. The specimen is then pinned out and fixed in 10% formalin before grossing. In general, one section per centimeter of the tumor is submitted; if the tumor is an intraductal papillary mucinous neoplasm (IPMN) or mucinous cystic neoplasm (MCN), and is noninvasive in the initial sections, it is necessary to return to the gross specimen and submit the entire lesion to ensure that invasive tumor is not missed. Additional sections should demonstrate the relation of the tumor to the various margins of excision, uninvolved pancreas, ducts, ampulla, duodenum, and soft tissue; one section from the proximal gastric resection margin, and one from distal duodenal resection margin should also be submitted. One section from the uninvolved pancreas and one from uninvolved ampulla are also submitted if not already sampled in the tumor sections. All identified lymph nodes in the soft tissue should be submitted for microscopic examination; there is no need to separate the nodes into groups because they are all considered regional. Microscopic examination of a minimum of 10 to 15 nodes has been recommended for Whipple specimens.

A. Acute pancreatitis is an inflammatory process in which pancreatic enzymes autodigest the gland. It is most commonly associated with biliary tract disease (such as gallstones) and alcohol abuse. The pancreas is swollen and edematous, and hemorrhagic in more severe cases. Chalky white fat necrosis may be evident. Histologically, mild pancreatitis is characterized by interstitial edema and leukocytic infiltration; the pancreatic parenchyma may be well preserved, with only limited necrosis. In severe cases, extensive necrosis and hemorrhage are seen (e-Fig. 17.1).^* Calcification and secondary infection may occur.

B. Chronic pancreatitis is an inflammatory process characterized by irreversible destruction of the exocrine component with acinar atrophy, mixed inflammatory cell infiltrates, and fibrosis with relative sparing of the islets of Langerhans (e-Fig. 17.2). Dilatation of the pancreatic ducts with proteinaceous, often calcified, secretions is characteristic. In later stages, the endocrine component may also be destroyed.