Ch. 14 - Pancreas & Biliary Tree Flashcards
What are the indications for pancreatobiliary FNA?
Unexplained pancreatic mass, bile stricture
How are pancreatic head masses sampled? Pancreatic body/tail?
Head masses are sampled through duodenum, body & tail through the stomach.
What complications are associated with pancreatic FNA?
Acute pancreatitis, perforation, cholangitis
What chemical testing can be performed on pancreatic cyst fluid?
CEA, amylase, KRAS/GNAS mutations.
What are the three normal components of pancreatic parenchyma?
Acinar cells, ductal cells, and islet cells (rare).
Describe the cytology of normal pancreatic acini.
Grapelike aggregates with eccentric nuclei, fine granular chromatin, and indistinct cell borders.
Describe the cytology of pancreatic ductal epithelium.
Flat cohesive sheets with even nuclear spacing (honeycombing). Should not have visible cytoplasmic mucin!
In what context may pancreatitis be sampled by FNA?
Only in chronic pancreatitis which may have mass-forming fibrosis. This is most prominent in autoimmune pancreatitis.
Describe the cytology of pancreatic ductal adenocarcinoma (PDAC)
High cellularity, irregular clusters with uneven distribution of cells (“drunken honeycomb”), marked atypia and anisonucleosis (>4:1).
Recall some variants of PDAC.
Adenosquamous, undifferentiated (with or without osteoclast-like giant cells), colloid, hepatoid, medullary, signet ring
Why is pancreatic intraepithelial neoplasia (PanIN) never sampled by FNA?
It is an in situ lesion and does not present with a mass.
Describe the cytology of pancreatic neuroendocrine tumor (PanNET).
Highly cellular with some pseudorosetting, eccentric nuclei with salt and pepper chromatin and rare endocrine atypia.
How are PanNETs graded?
By proliferation rate (1 / 2-20 / >20) and by Ki67 (<3% / 3-20% / >20%).
What may be functionally secreted by PanNETs, and why is that clinically significant?
Insulin, glucagon, somatostatin, VIP, serotonin, even ACTH and calcitonin. They manifest with clinical symptoms and are often detected earlier.
What are some specific markers for PanNET?
Besides the usual neuroendocrine markers, PanNETs stain for Islet-1 and PAX-8.
Describe the cytology of acinar cell carcinoma.
Solid-cellular pattern of monomorphic cells with granular cytoplasm (and background granules), smooth nuclei and prominent nucleolus.
Describe the cytology of solid pseudopapillary neoplasm.
Cellular aspirate with myxoid/hyalinized vascular stalks. Loose cells have finely vacuolated cytoplasm, grooved nuclei, and inconspicuous nucleoli. Background shows foam cells & debris (cystic degeneration).
What are some useful IHC markers for acinar cell carcinoma?
For SPN?
Which has a worse prognosis?
ACC: Trypsin (best), lipase, chymotrypsin, and phospholipase A2
SPN: Alpha1-antitrypsin, PR, CD56, CD10, CD117, and nuclear+cytoplasmic beta-catenin.
ACC has a worse prognosis.
Describe the cytology of pancreatoblastoma.
An epithelial component composed of syncytial groups and isolated cells with distinctive “squamoid corpuscles?, and a stromal component composed of primitive spindle cells.
Recall some different type of pancreatic cysts.
Pseudocyst, serous cystadenoma, lymphoepithelial cyst, mucinous cystic neoplasm, intraductal papillary mucinous neoplasm.
Describe the cytology of pseudocyst.
Thin nonmucinous fluid with inflammatory cells and hematoidin.
Describe the cytology of serous cystadenoma.
Low cellularity, clean background, maybe some siderophages and small clusters of glycogenated cells. Hard to diagnose on cytology…
Describe the cytology of lymphoepithelial cyst.
Anucleate squames (keratinaceous debris), squamous cells and lymphocytes. May have some cholesterol clefts; overall resembles an EIC.
In general, what cyst chemistry profile is expected from benign pancreatic cysts?
High amylase, low CEA, no KRAS or GNAS mutations.
Describe the cytology of MCN & IPMN.
Hypocellular, with variable amounts of mucin and variable dysplasia in the epithelial component.
Note: They cannot be distinguished from one another on cytology.
Distinguish the clinical features of MCN and IPMN.
MCN: Exclusively affects women, usually in the pancreatic tail. Does not communicate with ductal system.
IPMN: Affects both sexes, involves main duct, branch duct, or both.
Describe the cytology of ectopic splenic tissue in pancreas.
Highly vascular, with many lymphocytes. Distinguishing feature is CD8+ vessels on cell block.
How can KRAS/GNAS mutational analysis distinguish MCN and IPMN?
KRAS point mutations are seen in both MCN and IPMN. GNAS abnormalities are only seen in IPMN.
What are some useful stains to identify PDAC?
SMAD4 (DPC4), p53.
Distinguish between the clinical features of serous cystadenoma and lymphoepithelial cyst.
Serous cystadenoma: Affects women, usually in tail of pancreas. Can be microcystic, oligocystic…
Lymphoepithelial cyst: Affects mostly middle-aged men. Can be multifocal.
