GISTs, Carcinoids, Etc Flashcards
What cells do GISTs arise from?
Interstitial cells of Cajal (intestinal pacemakers in the myenteric plexus)
GISTs histologically stain positive for ?
c-kit (CD117) in 99%; CD34 in 80%; DOG1
Gastric carcinoids arise from?
enterochromaffin cells
GISTs occur most frequently in the ____
- stomach 2. small bowel 3. rectum; most common location in the small bowel is the jejunum and ileum
Survival indicators for GISTs
size at presentation, mitotic index, evidence of invasion into the lamina propria
Tumor that appears endoscopically as a submucosal smooth muscle tumor that extrinsically compresses the lumen
GIST
Staging workup of GIST
contrast enhanced CT Chest/ab/pelvis
GIST surgical treatment
wide local excision to negative gross margins. they do not require large margins and lymphadenectomy is not mandatory; take care to not disrupt capsule of the tumor
for a GIST, what is used for tumor grading
mitotic rate
Systemic therapy for ckit antibody in treatment for GIST
imatinib (gleevec)
What surgical margins should be obtained for gastric adenocarcinoma?
at least 5cm margins
Factors determining malignant potential of GISTs:
size of tumor, mitotic rate
Which patients with GISTs should receive gleevec?
those with tumors >3cm, >5mitotic figures/hpf, or those with metastatic disease
What is the criteria to undergo endoscopic mucosal resection for gastric cancer?
2cm less in diameter, well-differentiated, no penetration beyond submucosa (T1), no lymphovascular invasion, negative margins
Which gastric cancer is characterized by polymorphous infiltrate of small cells with associated reactive appearing follicles that express CD19, CD20, and CD22?
MALToma
How many lymph nodes should be obtained at minimum for gastric adenocarcinoma lymphadenectomy?
15 nodes
What diagnostic imaging can be used to diagnose bile reflux?
HIDA scan - shows bile in stomach and sometimes esophagus
A fasting serum gastrin ______ is pathognomic for gastrinoma.
1000 pg/mL
Diagnostic test for gastrinoma:
secretin stimulation test
When is neoadjuvant therapy recommended for gastric adenocarcinoma?
any node positive or locally advanced (T3) disease
Most predictive prognostic factor for GISTS:
mitotic index
True or false. Small bowel GISTS have a better prognosis than gastric GISTS.
false. it is worse
What is the current gold standard for adequate lymph node number in staging gastric cancer?
16 lymph nodes
characteristics of type 1 carcinoid:
most common; associated with pernicious anemia and chronic atrophic gastritis; less malignant potential and slow growing
characteristics of type 2 carcinoid:
occurs in MEN 1 and Zollinger Ellison syndrome; intermediate malignant potential
characteristics of type 3 carcinoid:
aggressive, solitary lesions associated with normal gastrin levels
How do GISTs metastasize?
hematogenous spread, most commonly to liver and peritoneal surfaces
What type of margins for resection are adequate for GISTs?
R0 or R1 margins
Most common risk factor for development of gastric adenocarcinoma:
H. pylori infection
When you use endoscopic mucosal resection with submucosal dissection for gastric cancer?
when less than or equal to 2cm diameter, well or moderately differentiated, without extension beyond submucosa (T1), no lymphovascular invasion, and negative margins
Histologic features of MALToma:
polymorphus infiltrate of small cells with associated reactive appearing follicles and expression of CD19, CD20, and CD22
Which subtype of MALToma is less likely to respond to abx eradication?
t(11;18) mutations; if this mutation is present radiation is indicated or rituximab
Other predictors of response to H. Pylori treatment for MALToma:
depth of penetration (deep to submucosa is less responsive)
absence of AP-12-MALT 1 translocation
gastric site (proximal is more worrisome)
microsatellite instability
advanced age
Treatment of MALToma that doesnt respond to H pylori or when patient is H pylori negative:
radiation treatment; chemo is used as salvage in those with radiation failure
True or false. Surgical excision of MALToma is appropriate.
false
Features of type 1 gastric neuroendocrine tumor:
female, multifocal, subcentimeter polypoid protrusions in body or fundus; associated with chronic atrophic gastritis and enterochromaffin-like cell hyperplasia; usually asymptomatic on presentation
True or false. Type 1 and Type 2 gastric neuroendocrine tumors can be managed with endoscopic removal or surveillance every 1-2 years when they are less than 1 cm without risk factors.
true
