Neuroendocrine tumors

Question 1

most common location of carcinoid tumors

Answer 1

GI tract 55%

Lungs 35%

Question 2

symptoms of carcinoid syndrome

Answer 2

flushing
diarrhea
hypotension
pruritis
telangiectasias on the face (prolonged vasodilitation)

Question 3

difference in pulmonary vs gastric NET flushing

Answer 3

gastric - short, patchy, intensely pruritic

pulmonary - hours - days, more severe

Question 4

biochemical mediators of carcinoid syndrome

Answer 4

serotonin (diarrhea)
histamine (flushing, wheezing)
kallikrein
bradykinin
tachykinin
prostaglandin

Question 5

carcinoid syndrome does NOT usually occur with midgut NETs except in which case

Answer 5

extensive liver mets

Question 6

what vitamin deficiency is associated with carcinoid syndrome

Answer 6

pellagra (vit B3 def) - large amounts of tryptophan are diverted from niacin synthesis to produce serotonin

Question 7

carcinoid tumors can also cause which endocrine syndromes

Answer 7

cushings (ACTH or CRH producing)

acromegaly (GHRH)

Question 8

5-HIAA is a metabolite of what

Answer 8

serotonin

Question 9

metabolism of tryptohpan

Answer 9

tryptophan - serotonin - 5-HIAA

Question 10

foods/meds that can cause false + 5-HIAA levels

Answer 10

tryptophan, serotonin

Question 11

diagnosis of carcinoid syndrome

Answer 11

elevated 5-HIAA in urine

Question 12

which test is NOT recommended in diagnosis of carcinoid syndrome

Answer 12

chromogranin A (nonspecific)

Question 13

which carcinoids can cause carcinoid syndrome but have normal 5-HIAA levels

Answer 13

foregut carcinoids (lack enzyme to convert tryptophan to serotonin

Question 14

best imaging to localize NETs

Answer 14

CT
MRI (better to eval for hepatic mets)
Octreoscan
DOTOATATE

Question 15

what % of carcinoid tumors are metastatic at the time of diagnosis

Answer 15

90%

Question 16

treatment of carcinoid syndrome

Answer 16

somatostatin analogues
telotristat (inhibits rate limiting step in serotonin synthesis)
chemo (respond poorly)
radioreceptor therapy
hepatic resection/embolization

Question 17

symptoms of carcinoid crisis

Answer 17

flushing, hypotension, wheezing/bronchospasm

Question 18

pretreatment of pts with carcinoid syndrome prior to going to the OR

Answer 18

octerotide 300-500mcg subQ 30-60 min prior to procedure

Question 19

which patients should received prophylaxis to prevent carcinoid crisis

Answer 19

symptomatic carcinoid syndrome

metastatic carcinoid - measure 5-HIAA levels and treat if elevated

Question 20

treatment of carcinoid crisis

Answer 20

iv octreotide
glucocorticoids
methotrimeprazine
methoxamine
phentolamine
ondansetron
glucagon
NO ADRENERGIC OR SYMPATHOMIMETIC AGENTS -- can make the condition worse

Question 21

% of PNETs that are nonfunctional

Answer 21

50-70%

Question 22

what % of insulinomas are benign?

Answer 22

80-90%

Question 23

what % of PNETs (besides insulinoma) are malignant?

Answer 23

50-80%

Question 24

what % of MEN1 pts have PNETs?

Answer 24

80-100%

Question 25

clinical manifestations of gastrinomas

Answer 25

severe peptic ulcer disease secretory diarrhea also known as Zollinger-Ellison syndrome

Question 26

typical locations of gastrinomas

Answer 26

70% duodenum | 25% pancreatic islets

Question 27

diagnosis of gastrinoma

Answer 27

serum gastrin level > 1000 gastric pH < 4.0 secretin stimulation test with gastrin rise > 200 pg/mL off PPI for 1 week

Question 28

functional test for diagnosis of gastrinoma

Answer 28

secretin stim test | gastrin rise of > 200 pg/mL 15 minutes after IV secretin administration

Question 29

imaging modalities for gastrinoma localization

Answer 29

``` CT/MRI EUS DOTATATE Octreoscan transportal venous sampling selective arterial secretin stimulation ```

Question 30

treatment of gastrinomas (benign)

Answer 30

surgery high dose ppi somatostatin analogues (octreotide, lanreotide) H2 blockers refractory - vagotomy or subtotal gastrectomy

Question 31

treatment of malignant gastrinomas

Answer 31

surgery | liver mets - surgery, embolization, liver xplant, radioreceptor therapy, chemo

Question 32

presentation of glucagonomas

Answer 32

``` DM wt loss anemia necrolytic migratory erythema VTE ```

Question 33

diagnosis of glucagonoma

Answer 33

glucagon levels > 500 pg/mL (but not always this high)

Question 34

localization of glucagonomas

Answer 34

``` same as gastrinomas: CT/MRI EUS DOTATATE Octreoscan transportal venous sampling selective arterial secretin stimulation ```

Question 35

treatment of glucagonomas

Answer 35

``` surgery for localized disease somatostatin analogues liver-directed therapies chemo radioreceptor therapy tx overall similar to gastrinomas** ```

Question 36

tx for skin rash associated with glucagonomas

Answer 36

zinc, amino acid infusions

Question 37

characteristics of somatostatinomas

Answer 37

``` DM weight loss steatorrhea hypochloridia cholelithiasis ```

Question 38

diagnosis of somatostatinoma

Answer 38

elevated serum somatostatin level

Question 39

treatment of somatostatinomas

Answer 39

surgery

Question 40

characteristics of VIPomas

Answer 40

watery diarrhea kypokalemia achlorhydria

Question 41

diagnosis of VIPoma

Answer 41

elevated serum VIP level

Question 42

treatment of VIPoma

Answer 42

surgery