Flashcards in Neoplasia III: Carcinoid, GIST, Lymphoma (aka zebra lecture) Deck (38)
Pathophys of gastric carcinoid tumors?
1. Chronic gastritis or Gastric acid suppression
2. Hypergastrinemia compensatory response
3. Gastric diffuse neuroendocrine hyperplasia
Micro morphology of gastric carcinoid tumors?
islands or sheets of uniform cohesive cells, often (+) for NE markers such as chromogranin
What other characteristics/presentations are associated with gastric carcinoid tumors that secrete gastrin?
What other characteristics/presentations are associated with gastric carcinoid tumors that DON"T secrete gastrin?
many mets at dx
How do ileal tumors present?
with carcinoid syndrome
(flushing, bronchospasm, incr motility, R cardiac valve thickening)
Most important prognostic factor for GI carcinoid?
1. foregut--rarely met, cured by srx
2. midgut--multiple, aggressive
3. hindgut--found incidentally
What labs are associated with Z-E syndrome?
Fasting gastrin level >1000 pg/ml
What diagnostic tests are used to dx Z-E syndrome?
Secretin stimulation test (measure gastrin levels incrementally after IV secretin administered)
positive = gastrin incr by >200
Treatment of Zollinger-Ellison syndrome, if solitary + non-met?
Medical management (PPI, LA somatostatin)
Epidemiology of Intestinal Neuroendocrine Tumor (Carcinoid)?
Typically in late middle-aged patients
Most common location of Intestinal Neuroendocrine Tumor (Carcinoid)?
Ileum and appendix
**often at multiple sites
Most frequent symptom of Intestinal Neuroendocrine Tumor (Carcinoid)?
Common complication of Intestinal Neuroendocrine Tumor (Carcinoid)?
Most common neoplasm of appendix?
Intestinal Neuroendocrine Tumor (Carcinoid)
What is carcinoid syndrome?
colicky abdominal pain
Right heart endocardial fibrosis (50%)
**caused by vasoactive polypeptides, serotonin
How do you diagnose carcinoid syndrome?
High urine 5-hydroxyindole acetic acid (5-HIAA) (but limited sensitivity and specificity)
How do they present in colon? In rectum?
most commonly presents as large mass in right colon
rectum = usually only found incidentally
What type of cells are present in GIST?
spindle, epithelioid or occasionally pleomorphic mesenchymal cells that often express the KIT (CD117) protein
The best predictor of biological behavior of GISTs is a combination of:
**GIST should be "regarded as malignant"
GIST can be stained for:
CD177 (via antibodies)
Epidemiology of GIST?
Most common location of GIST?
stomach and small intestine
GIST are thought to derive from or differentiate toward:
interstitial cells of Cajal
(GI PM cells that form the interface between the autonomic innervation and smooth muscle cells of the gut)
Most GIST have mutations in:
KIT transmembrane receptor TK
**activates as oncogene, w/ (+) immunostain for CD117
GIST: Method of detection?
Endoscopic US-guided fine needle aspiration
Trx for GIST?
imatinib (TKI), if mets
What causes Post-Transplant Lymphoproliferative Disorder?
Immunosuppression can allow B cells infected with Epstein-Barr virus to proliferate in an uncontrolled manner.
What may control Post-Transplant Lymphoproliferative Disorder?
If the immunosuppression can be safely decreased, sometimes the proliferation will come under control, sometimes not.
What are the 2 types of GI lymphomas?
~ 50% = low grade mucosa-associated lymphoid tissue “MALTomas”
~50% = aggressive diffuse large B-cell lymphomas