GASTROENTEROLOGY ARTICLE OF THE WEEK
September 22, 2005
Warner RP. Enteroendocrine tumors other than carcinoid: A review of clinically significant advances. Gastroenterology 2005;128:1668-1684.
1. Other areas where neuroendocrine tumors may arise include
a. lung (small cell ca)
b. pituitary
c. liver
d. thymus
e. prostate
f. skin (Merkel cell carcinoma)
2. MEN-1 syndrome
a. Associated with a mutation on chromosome 11q 13
b. Most commonly presents with parathyroid hyperplasia, pancreatic PPoma or gastrinoma
c. Over 60% of Z-E syndrome patients have MEN-1
d. Most gastrinomas associated with the MEN syndrome are located in the duodenum
e. Only 4% to 5% of insulinomas are associated with MEN-1
3. Somatostatin receptor scintigraphy (SRS):
a. is the gold standard and most sensitive modality for the detection of most NETs
b. Is most sensitive in the detection of Insulinomas
c. Can differentiate pancreatic adenocarcinoma from a NET
d. SRS is only positive if the NET is a functioning tumor
e. Will rarely be positive in other types of tumors/conditions
f. SRS is the best initial test for localizing and indicating the extent of metastasis of gastrinoma
g. The more strongly positive the SRS, the more likely a NET will respond to octreotide therapy
h. A positive scan will occur only if the tumor expresses the somatostatin receptor subtype 2 or 5 (SSTr2 or SSTr5), 80% express SSTr2.
4. Clinical features of gastrinomas
a. Ulcer disease is the presenting symptom in >80%.
b. Most gastrinomas are in the pancreas
c. MEN-1 associated gastrinomas are rarely curable by surgery
d. Presence of metastasis at diagnosis is the most important predictor of survival
e) Octreotide therapy may improve survival in malignant gastrinomas
True or False
5. The embryologic origin of the enteroendocrine cells is the neural crest.
6. The most common functioning PET is insulinoma (17%) followed by gastrinoma (15%)
7. Neurofibromatosis type 1 is often associated with somatostatinomas
8. The most common cause of death from pancreatic endocrine tumors is liver failure
9. Up to 10% of autopsies of patients dying from other causes may uncover clinically insignificant PETs.
10. Non-functioning PETs usually secrete pancreatic polypeptide (PP).
11. Insulinomas have the lowest malignant potential, up to 60% of other NETs will present with metastasis to the liver.
12. A falsely elevated serum chromogranin-A can be seen in patients with pernicious anemia
13. The most important factor in determining degree of malignancy is the size of the tumor at presentation
14. The best non-specific marker for the presence of a non-insulionoma NET is the serum level of CgA (chromogranin-A)
15. Octreotide will be most effective in NETs that express somatostatin receptors SSTr2 and SSTr5, 80% of NETs express SSTr2.
16. Dermatitis (necrolytic migrating erythema), diabetes, DVT and depression are the common presenting symptoms and signs of somatostatinomas
17. PET scan is useful in detecting most NET metastasis
18. Bone scan is the most sensitive test to detect bone metastasis from NETs
19. An insulinoma which does not light up on SRS should not be treated with octreotide
20. Vipomas are located in the pancreas in 90% of cases, presentation is usually with secretory diarrhea, electrolyte disturbance and flushing (of the face, not the toilet)
21. Diabetes, gallstones and steatorrhea are the classical triad of somatostatinomas