Neoplasia of intestines

Question 1

What might explain the lower incidence of malignancy in the small intestine?

Answer 1

rapid transit time of enteric contents through the small bowel
lower concentrations of bacteria
lots of immune surveillance with intramural lymphoid tissue.

Question 2

____ tumors are a subset of neuroendocrine tumors that appear in the GI tract

Answer 2

carcinoid

Question 3

What might explain the increasing incidence of carcinoid tumors?

Answer 3

detection bias- modern CT imaging

Question 4

Caucasian patients tend to have more _____ carcinoids and Africans have more ______ carcinoids

Answer 4

bronchial

rectal

Question 5

What genetic syndromes are associated with carcinoid?

Answer 5

Multiple endocrine neoplasia- MEN1 gene mutations, associated with parathyroid and pituitary tumors

von Hippel-Lindau- autosomal dominant, associated with renal cell carcinoma, cerebellar hemangioblastoma, pheochromocytoma

Question 6

_________staining is performed to identify and classify carcinoid tumors

Answer 6

immunohistochemical

Question 7

Carcinoid arises from _____ cells in the gut

Answer 7

Kulchitsky

Question 8

What are the classic findings of carcinoid syndrome?

Answer 8

flushing
diarrhea
bronchospasm
right heart failure

Question 9

What causes flushing in carcinoid syndrome?

Answer 9

catecholamine mediated
NOT caused by serotonin
Vasodilation can be due to substances released by the tumor cells, including bradykinin, substance P, tachykinins, and prostaglandins

Question 10

How is flushing in carcinoid syndrome treated?

Answer 10

antihistamines

Question 11

What causes diarrhea in carcinoid syndrome?

Answer 11

increased gut motility mediated by serotonin

Question 12

Describe the heart disease seen in carcinoid syndrome

Answer 12

late complication
Fibrotic deformation of the tricuspid and pulmonary valves usually leads to pulmonary stenosis and tricuspid insufficiency

Question 13

In carcinoid, treatment with _____ appears to slow progression of heart disease

Answer 13

octreotide

Question 14

How is carcinoid tumor diagnosed?

Answer 14

24 hour 5-HIAA urine collection
chromogranin A
CT and MRI imaging including octreotide scanning

Question 15

Other than carcinoid, what are possible causes of elevated chromogranin A?

Answer 15

PPIs, H2 blockers

hepatic or renal insufficiency

Question 16

Describe histopathology of neuroendocrine tumors

Answer 16

heavily vascularized
salt and pepper chromatin
trabeculations within stroma
immunochemistry for chromogranin or synaptophysin

Question 17

List biochemical manifestations of carcinoid

Answer 17

Glucose intolerance
Low-grade anemia
Electrolyte imbalances indicative of chronic diarrhea

Question 18

How is grade of carcinoid tumor quantified?

Answer 18

Ki-67 proliferation index

mitotic count

Question 19

______ is the gold standard in treatment of carcinoid tumors

Answer 19

surgical resection
extend depends on risk of recurrence. ex tumor less than 1 cm- simple appendectomy; tumor >2 cm- appendectomy with R hemicolectomy

Question 20

_______ can offer symptomatic relief when curative surgery is not possible

Answer 20

surgical debulking

Question 21

________ is use for symptomatic tumors as an alternate to surgery when cure is not possible

Answer 21

ablation

Question 22

______ was developed for symptomatic relief but actually slows progression/ improves progression free survival

Answer 22

octreotide

Question 23

______ and ______ have FDA approval for treatment of pancreatic NET

Answer 23

Sunitinib and everolimus, relatively ineffective in carcinoid subset

Question 24

Low grade carcinoid tumors are often chemotherapy _____

Answer 24

resistant

Question 25

Intravenous or subcutaneous _____ inhibits carcinoid flush, but is not practical for therapy because it has a half-life of less than 2 minutes

Answer 25

somatostatin

Question 26

MALTomas are ______ lymphomas associated with H pylori infection

Answer 26

B cell

Question 27

What is appropriate treatment for localized MALTomas?

Answer 27

treatment to eradicate H. pylori- can lead to complete and sustained response

Question 28

What is appropriate treatment to eradicate H pylori?

Answer 28

PPI plus amoxicillin plus clarithromycin (or metronidazole)

Question 29

In MALToma, what are predictors of worse outcome?

Answer 29

lymph node involvement | high grade features

Question 30

_______ is a rare B cell non-Hodgkin lymphoma that can occur in the GI tract

Answer 30

Mantle cell lymphoma

Question 31

Mantle cell lymphoma in the gut is sometimes called _______ because it presents as a field of polyps with a lymphoid rich infiltrate

Answer 31

lymphatomatous polyposis

Question 32

Mantle cell lymphoma is ______ to most current chemotherapy regimens

Answer 32

refractory

Question 33

_______ can have GI involvement but is rare

Answer 33

follicular lymphoma

Question 34

GIST arises from what cell type?

Answer 34

Interstitial cells of Cajal | pacemaker cells of the gut

Question 35

How does GIST present?

Answer 35

vague abdominal discomfort, nausea, early satiety, and very rarely cause obstructive symptoms

Question 36

What is the most common site of GIST?

Answer 36

stomach> small intestine> rectal

Question 37

Even low grade GISTs have some ______ potential

Answer 37

malignant

Question 38

_____ is pathognomonic for GIST

Answer 38

c-kit mutation

Question 39

Treatment of GIST involves surgical resection and adjuvant therapy with ____

Answer 39

imatinib | originally thought 1 year, now may be lifetime

Question 40

Imatinib was designed to target bcr-abl fusion protein in CML but has off-target effects on ______

Answer 40

tumors overexpressing c-kit

Question 41

List familial syndromes possibly associated with GIST

Answer 41

NF1 and Carney triad