Pathology of the Pancreas Flashcards
What is an annular pancreas?
developmental malformation in which the pancreas forms a ring around the duodenum (risk of duodenal obstruction).
What is ACUTE pancreatitis?
inflammation and hemorrhage of the pancreas due to autodigestion of pancreatic parenchyma by pancreatic enzymes (from premature activation of TRYPSIN leading to activation of other pancreatic enzymes).
What type of necrosis does ACUTE pancreatitis cause?
liquefactive hemorrhage (coagulative) necrosis of the pancreas and fat necrosis of the peripancreatic fat.
What are the 2 most common causes of ACUTE pancreatitis?
ALCOHOL and GALLSTONES (both of which block the sphincter of Odi, either by a stone or increased contraction of the sphincter).
What are some other causes of ACUTE pancreatitis?
- trauma (especially automobile accidents involving children due to the seat belt compressing the abdomen instead of the waist causing ischemic injury).
- hypercalcemia (calcium is an activator of enzymes).
- hyperlipidemia
- drugs (furosemide, estrogens)
- scorpion stings
- mumps
- and rupture of a posterior duodenal ulcer (because the head of the pancreas sits slightly posterior to the duodenum).
- inherited mutations in genes encodign trypsinogen (PRSS1) and trypsin inhibitor (SPINK1).
What are the clinical features of ACUTE pancreatitis?
- epigastric abdominal pain that radiates to the back.
- nausea and vomiting.
- periumbilical and flank hemorrhage (necrosis spreads into the periumbilical soft tissue and retroperitoneum).
- elevated serum lipase and amylase (lipase is more specific).
- hypocalcemia (calcium is consumed during saponification in fat necrosis).
What are the 4 complications of ACUTE pancreatitis?
- shock (due to peripancreatic hemorrhage and fluid sequestation).
- pancreatic pseudocyst (formed by fibrous tissue surrounding liquefactive necrosis and pancreatic enzymes; lack epithelial lining. This presents as an abdominal mass with elevated amylase and rupture is assoicated with release of enzymes into the abdominal cavity).
- pancreatic abscess (often due to E. coli, presents with abdominal pain, high fever, and persistently elevated amylase).
- DIC (due to enzymes destroying Co-A factoras in the blood) and ARDS (from enzymes destroying capillary-alveolar interface).
What defines CHRONIC pancreatitis?
- fibrosis of pancreatic parenchyma from chemokines, TGF-B and PDGF stimulating production of myofibroblasts (most often secondary to recurrent acute pancreatitis) from alcohol (adults) and cystic fibrosis (children; CFTR gene mutation= decreased pancreatic bicarb secretion leading to protein plugging).
- may see damage to ENDOCRINE pancreas as well.
What are the clinical features of CHRONIC pancreatitis?
- epigastric abdominal pain that radiates to the back in addition to pancreatic insufficiency (results in malabsorption with steatorrhea and fat soluble vitamin deficiencies; A, D, E, and K).
- dystrophic calcification of pancreatic parenchyma on imaging (chain of lakes pattern due to dilation of pancreatic ducts).
- secondary DM (rare but can occur as a late complication due to destruction of islets).
- increased risk for pancreatic carcinoma
Are amylase and lipase useful serologic markers of chronic pancreatitis?
NO (only acute).
What is pancreatic carcinoma?
- adenocarcinoma arising from the pancreatic DUCTS, most commonly seen in the elderly.
- most tumors arise in the head of the pancreas, are usually hard stellate, gray-white and poorly defined.
What are the 2 major risk factors for pancreatic carcinoma?
- smoking
2. chronic pancreatitis
What are the clinical features (usually occur late in disease) of pancreatic carcinoma?
- epigastric abdominal pain and weight loss.
- obstructive jaundice (due to leaking of conjugated bilirubin into the blood) with pale stool and palpable gallbladder (from tumors in head of pancreas).
- secondary DM (from tumors in the body or tail).
- pancreatitis
- migratory thrombophlebitis (TROUSSEAU syndrome)= presents as swelling, erythema, and tenderness in the extremities (10% of patients).
- serum tumor marker is CA 19-9.
How do you treat pancreatic carcinoma?
surgical resection of the head and neck of pancreas, proximal duodenum, and gallbladder (WHIPPLE PROCEDURE).
What is the prognosis for pancreatic carcinoma?
very bad (1-year survival is
How is trypsin related to the clotting and complement systems?
trypsin converts prekalikrein to its activated form, initiating the actions of the kinin system and activating Hageman factor (factor XII) for clotting.
What are some ways that pancreatic enzymes become inappropriately activated in acute pancreatitis?
- pancreatic duct obstruction= increase in ductal pressure causing enzyme rich fluid to accumulate in the interstitium.
- primary acinar cell injury= mumps, trauma, shock, ischemia.
- defective intracellular transport of proenzymes within acinar cells.
What inappropriate pancreatic enzyme is responsible for hemorrhage?
elastase
What is lymphoplasmacytic sclerosing pancreatitis?
autoimmune form with duct centric mixed inflammatory infiltrate, venulitis and increased number of plasma cells.
*clinically mimics pancreatic cancer, but can be treated with steroids.
What are pancreatic congenital cysts?
- thin, fibrous capsule lined by a single layer of cuboidal epithelium containing serous fluid that arises from anomalous development of the pancreatic ducts.
With what may congenital cysts be seen?
polycystic ovarian syndrome and von Hippel-Lindau disease
What are serous cystadenomas of the pancreas?
BENIGN small cysts surrounded by glycogen rich cells.
- cysts contain clear, straw-colored fluid
- more common in women
What are mucinous cystic neoplasms?
- cysts surrounded by columnar epithelium and filled with thick serous fluid.
- arise in the body or tail of pancreas and can be associated with invasive cancer.
- painless and slow growing
- most in women
- larger than cystadenomas
- KNOW PICTURE
What are intraductal papillary mucinous neoplasms?
- mucin secreting intraductal neoplasms that are more common in men.
- involve the head of the pancreas more often
- lacks dense stroma
- benign or malignant (remember invasion is a sign of malignancy).
- KNOW PICTURES
What is a solid-pseudopapillary neoplasm?
- unusual, well circumscribed masses that have both solid and cystic components to them.
- seen in young women
- have mutations of beta catenin.
What is important about pancreatic intraepithelial neoplasias (PaINs)?
they are often found adjacent to infiltrating cancer (stratification of nuclei, hyperchromasia, high N/C ratio)…
What is the most frequently altered gene in pancreatic cancer?
K-RAS gene (remember RAS activates intracellular signal transduction pathways therefore activating transcription factors).
What gene is often inactivated in pancreatic cancer?
- CDKN2A(16)= tumor suppressor gene
- p53= tumor suppressor gene that acts as a cell cycle checkpoint and can induce apoptosis.
Where does metastasis of pancreatic carcinoma normally occur?
liver, lungs, and bones
What is acinar cell carcinoma?
prominent acinar cell differentiation with formation of zymogen granules and production of TRYPSIN and LIPASE.
*SEE PICTURES
What is pancreatoblastoma?
rare malignant tumors seen in children that are SQUAMOUS ISLANDS mixed with acinar cells
