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Flashcards in Pancreas Deck (15)
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1

Pancreatic Agenesis

  • absence of pancreas, associated with severe malformations.
  • not compatible with life.

2

Pancreas Divisum

  • most common pancreatic congenital abnormality (3-10% incidence).
  • failure of ventral and dorsal ftal duct systems to fuse ⇒ most pancreatic secretions drain through minor papilla.
  • predisposes to chronic pancreatitis.

3

Annular Pancreas

  • bandlike ring of normal pancreatic tissue encircles second portion of duodenum.
  • can cause duodenal obstruction.

4

Ectopic Pancreas

  • 2% incidence.
  • can be found in stomach, duodenum, jejunum, Meckel diverticulum, ileum.
  • submucosal, single or multiple, a few mm - cm.  
  • can cause inflammation, pain, and rarely bleeding.

5

Acute Pancreatitis

  • reversible parenchymal damage associated with inflammation.
  • 80% with biliary tract disease (gallstones) or alcoholism.
  • 10-20% idiopathic.
  • hereditary = recurrent bouts of pancreatitis starting as kid.  autosomal dominant mutation in PRSS1 ⇒  activated trypsin resistant to self-inactivation.
    • can have autosomal recessive mutation in serine protease inhibitor Kazal type 1 gene (SPINK1). fials to inhibit trypsin activity.
  • morphology: mild interstitial edema and inflammation to extensive necrosis and hemorrhage.
    • vascular leakage ⇒ edema; necrosis of regional fat by lipolytic enzymes; acute inflammation; proteolytic destruction of pancreas; vascular injury with hemorrhage.
    • mild = edema, fat necrosis, acute inflammation.
    • acute necrotizing pancreatitis = gray-white parenchymal necrosis and chalky white fat necrosis.
    • acute hemorrhagic = patchy red-black hemorrhage with fat necrosis.
  • pathogenesis: from parenchymal autodigestion from pancreatic enzymes (inappropriate inactivation of trypsinogen).
    • trypsin activated in pancreas allows proenzymes to be activated and prekallikrein to kallikrein which activates kinin system and clotting.
    • causes inflammation and thrombosis with proteolysis, lipolysis, and hemorrhage.
    • pancreatic duct obstruction = gallstones or sludge in apmulla.  lipase ⇒ fat necrosis.  inflammation and edema compromises vascular flow, causes ischemia.
    • primary acinar cell injury = from viruses (mumps), drugs, trauma, or ischemia.
    • defective intracellular transport of proenzymes = misdirected toward lysosomes.  hydrolyzes proenzymes and releases.
    • alcohol = toxic to pancreatic acinar cells.  causes functional obstruction by contracting spincter at ampulla and ↑ pancreatic protein secretion ⇒ inspissated protein plugs.
  • presentation: abd pain, nausea, anorexia, ↑ plasma levels amylase and lipase.  
    • full blown = medical emergency with intense abd pain, peripheral vascular collapse, shock.  death in 5% from shock, ARDS, or acute renal failure.
    • labs: ↑ serum amylase, glycosuria, hypocalcemia from fat necrosis.
    • necrotic debris can become infected.
  • tx: restricting oral intake, analgesia, nutrition, volume support.  
  • complications: pancratic abscesses, pancreatic pseudocysts.

6

Chronic Pancreatitis

  • inflammation with irreversible parenchymal destruction and fibrosis.
  • long-term alcohol abuse common.
  • also from ductal obstruction from pseudocysts, tumors, orcalculi, pancreas divisum, hereditary pancreatitis, CFTR mutations (⇒ ↓ ductal cell bicar secretion, promotes plugging).
  • pathogenesis: from ductal obstruction by concretion, toxic effects (alcohol and metabolites), oxidative stress. 
  • morphology: replacement of pancreatic acinar tissue by dense fibrous CT, relative sparing of islets of Langerhans, variable dilation of pancreatic ducts.  pancreas hard with focal calcifications.
    • lymphoplasmacytic sclerosing pancreatitis = autoimmune pancreatitis.  have mixed inflammatory cell infiltrates, venulitis, IgG4-producing plasma cells.  responds to steroids.
  • presentation: can be silent or recurrent pain and/or jaundice.  precipitated by alcohol abuse, overeating, opiates.
    • late complications = malabsorption, diabetes mellitus, pseudocysts.
    • 50% mortality within 20-25 yrs.

7

Congenital Pancreatic Cysts

  • from anomalous development of pancreatic ducts.
  • congenital polycystic disease = coexist in kidney and liver
  • von Hippel-Lindau disease = see pancreatic cysts and angiomas of CNS.
  • unilocular, thin-walled, cuboidal epithelial lining.

8

Pancreatic Pseudocysts

  • collections of necrotic-hemorrhagic material rich in pancreatic enzymes.  from walled off areas of fat necrosis.
  • are 75% of pancreatic cysts.
  • encircled by fibrosed granulation tissue.
  • from bouts of acute pancreatitis or trauma.
  • spontaneously resolve or get infected or compress adjacent structures.

9

Serous Cystadenoma

  • painless, slow growing mass.
  • women >60yrs.  
  • solitary, well circumscribed nodules with central stellate scar.
  • made of numerous 1-3mm cysts lined by glycogen-rich cuboidal epithelium with serous watery fluid.
  • benign and cured by resection.

10

Mucinous Cystic Neoplasm

  • painless slow growing mass. 
  • multiloculated cystic neoplasms, filled with thick mucinous material.  lined by mucin-producing columnar cells within dense stroma.
  • 95% in women, masses in body or tail of gland.
  • 1/3 lesions have invasive adenocarcinoma.

11

Intraductal Papillary Mucinous Neoplasm (IPMN)

  • more common in men.  arise in head of gland.
  • 10-20% multifocal.  lack dense stroma, involve a larger pancreatic duct, have malignant potential.

12

Solid-Pseudopapillary Tumor

  • round, well circumscribed neoplasm.  have solid and cystic regions.  
  • mainly in young women.  cause abd discomfort from large size.
  • associated with activating mutation of beta-catenin.
  • locally aggressive but cured by resection.

13

Pancreatic Carcinoma

  • an infiltrative ductal adenocarcinoma.  4th leading cause of cancer death is US.
  • progress from non-neoplastic epithelium to small ductal non-invasive lesion to invasive carcinoma.
    • precursor lesion = pancreatic intraepithelial neoplasms (PanINs). have genetic and epigenetic alterations with short telomeres.
  • KRAS = most altered gene (90%) ⇒ active protein, ↑ Fos and Jun transcription factor activation.
  • CDKN2A (p16) = inactivated in 95%
  • SMAD4 = tumor suppressor gene, inactivated in 50%.  encodes TGF-beta receptor signal transdution.
  • p53 = inactivation means no apoptosis or cell senescence.
  • pathogenesis: 80% btw ages 60-80yrs. smoking increases risk 2x.  risk from chronic pancreatitis, fat rich diets, family history of pancreatic cancer, diabetes mellitus.
  • morphology: 60% in head of gland, 15% in body, 5% in tail, 20% diffuse.
    • highly invasive, intense host scarring response (desmoplasia).
    • in head = obstruct distal common bile duct ⇒ jaundice. 
    • body and tail = silent for long time.  large or metastatic when discovered.  extensive perineural and vascular invasion.
    • cells form glandular patterns resembling ductal epithelium.
    • adenosquamous carcinoma = squamous and glandular differentiation.
    • undifferentiated carcinoma = multinucleated osteoclast-like giant cells.
  • presentation: weight loss and pain.  jaundice if in head.  metastases common (liver), 80% unresectable at presentation. 
    • 80% first year mortality.
    • Trousseau syndrome = migratory thrombophlebitis can occur with pancreatic neoplasms.

14

Acinar Cell Carcinoma

  • have acinar cell differentiation, zymogen granules, produce exocrine enzymes (trypsin)
  • lipase release can cause metastatic fat necrosis in 15%.

15

Pancreotoblastoma

  • rare malignant tumor in childhood.
  • squamous islands mixed with acinar cells.