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