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Cameron Stomach > Stomach_ZES > Flashcards

Stomach_ZES Flashcards

1
Q

Where is gastrin synthesized?

A

G cells, open-ended endocrine cells found predominantly in the gastric antrum

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2
Q

In general gastrin release is stimulated by:

A

Digestive proteins (e.g. phenylalanine and tryptophan), calcium, epinephrine, achlorhydria and gastric distension

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3
Q

Vagal parasympathetic control of gastrin physiology is stimulatory or inhibitory?

A

Both

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4
Q

T/F: atropine blocks gastrin stimulation?

A

TRUE

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5
Q

Gastrin release is stimulated by what specific proteins?

A

bobesin or gastrin releasing peptide (GRP

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6
Q

Gastrin is inhibited by what specific hormones?

A

Somatostatin, secretin, glucagon, gastric inhibitory peptide (GIP), vasoactive intestinal peptide (VIP)

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7
Q

What oncogenes are implicated for in gastrinomas pathogenesis?

A

c-myc and Her-2/neu

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8
Q

What tumor-supressor genes are implicated in gastrinoma pathogenesis?

A

MEN-1, DPC4/Smad and p16INK4a

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9
Q

What are the markers for aggressive biologic behavior of neuroendocrine tumors (e.g. gastrinomas)?

A

Oncogenes, RET-protooncogenes being present. Over expression of EGF-R, IGFlr, chromosomal abnl, chromosome 1q, chromosome 22q and X chromosome.

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10
Q

MEN-1 tumor-suppressor gene is on what chromosome?

A

11q13

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11
Q

MEN-1 encodes what protein?

A

menin

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12
Q

What does menin do?

A

It is a nuclear protein that alters tumor growth factor beta signanling, regulates NFKB transcription and man fxn in DNA repair and synthesis.

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13
Q

When is Zollinger-Ellison diagnosed

A

Usually in the 5th decade of life

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14
Q

Patients with MEN-1 have onset of ZES at what age

A

33 years versus 44 years in sporadic cases

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15
Q

What should prompt a physician to test for ZES?

A
  1. Combination of abdominal pain, diarrhea, wt loss. 2. Recurrent or refractory ulcers. 3. Prominent gastric rugal folds. 4. GI symptoms w/ or w/o ulcers occuring in an MEN-1 pt.
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16
Q

What is the initial diagnostic test for a patient suspected of having ZES?

A

Fasting serum gastrin when patient has been off PPIs for 72 hours.

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17
Q

Is fasting hypergastrinemia along enough to establish the dx of ZES?

A

No

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18
Q

Give the differential for hypergastrinemia

A

Pernicious anemia, atrophic gastritis, pharmacologic suppression, H. pylori infection, GOO, antral G-cell hyperplasia, reatined antrum, short bowel syndrome, renal failure.

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19
Q

After a fasting serum gastrin, what is the next test in the work-up for ZES?

A

Gastrin-stimulation test

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20
Q

Is it necessary to discontinue PPIs for the secretin stim test for ZES?

A

No

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21
Q

How is a secretin stimulation test for ZES done?

A

Give 0.4 mg/kg of secretin by IV push, then measure gastrin at 0, 2, 5, 10, 15 and 30 minutes

22
Q

What is a positive secretin stimulation test for ZES?

A

An increase in postsecretin gastrin of 200 pg/mL. However, most authorities use an increment of 110 pg/mL

23
Q

What % of patients with a gastrinoma have MEN-1?

A

25%

24
Q

All patients with a gastrinoma should be screened for?

A

MEN-1 with a serum measurement of calcium, phosphorus, parathyroid hormone and prolactin at presentation and periodically during follow-up.

25
Q

What imaging tests are used to localize a gastrinoma?

A

US, CT, MRI, angiography, somatostain scintigraphy with octreotide, EUS or selective arterial secretin or calcium stimulation with sampling from the hepatic veins.

26
Q

What is the difference in sensitivity of EUS in detecting gastrinomas in the duodenum vs the pancreas?

A

Pancreas: 75-100%. Duodenum: 25-63%.

27
Q

What is the medical treatment of gastric acid hypersecretion for ZES patients?

A

PPIs, often at doses greater than commonly recommended for typical ucler disease.

28
Q

If the primary gastrinoma is not found on imaging, what is indicated?

A

Surgical exploration.

29
Q

What % of patients with negative imaging will NOT have their primary gastrinoma found on ex lap?

A

15%.

30
Q

Give the borders of the gastrinoma triangle

A

Confluence of cystic and CBD superiorly, 2nd and 3rd portions of the duodenum inferiorly, and neck/body of the pancreas medially

31
Q

Principles of surgical exploration for finding the gastrinoma

A

Wide Kocher maneuver, mobilization of body and tail for bimanual palpation, intraoperative US, duodenotomy to explore the duodenal mucosa and sampling of lymph nodes in the gastrinoma triangle.

32
Q

In the duodenum, where are most gastrinoma primaries located?

A

In the 1st and 2nd portion

33
Q

How large are most gastrinoma primaries in the duodenum?

A

Often < 2mm, most are <1 cm

34
Q

When a nodule suspected to be a gastrinoma is found on exploration of the duodenum, what is the next step?

A

Send it for frozen section - can be brunner’s gland hyperplasia

35
Q

Can lymph nodes be a primary source of gastrinomas?

A

Yes - literature suggests 10% of sporadic cases

36
Q

When can one be diagnosed with a lymph node primary gastrinoma?

A

The patient cannot have MEN-1 and only after 10 years after suspected diagnosis as the primary can be found on another exploration

37
Q

What is required of pts diagnosed with lymph node primary gastrinoma?

A

Yearly fasting and secretin-stimulated serum gastrin levels

38
Q

When can pancreatic gastrinomas be enucleated?

A

If they are < 2cm and do not involve the duct

39
Q

If a gastrinoma either involves the pancreatic duct or is >2 cm what surgery is indicated?

A

Pancreaticoduodenectomy. Lesions in the body and tail - a distal pancreatectomy and splenectomy is required

40
Q

What is the definition of biochemical cure following surgery for sporadic ZES?

A

Normal fasting and secretin-stimulation gastrin level

41
Q

What is the initial cure rate for sporadic ZES?

A

35-60%

42
Q

With long-term follow-up, recurrent hypergastrinema may occur in what % of patients?

A

40%

43
Q

Surgical resection increases disease-specific survival for sporadic ZES by what % at 15 and 20 years?

A

15 years: 98% for pts who underwent an operation and 74% for non-op pts. 20 years: 60 (op) and 20% (non-op)

44
Q

Why should an MEN-1 patient undergo parathyroid surgery (if indicated) before surgery for ZES?

A

Removing the constant stimulation for hypercalcemia (parathyroid) reduces the serum gastrin levels

45
Q

What procedure is done for hyperparathyroidism in MEN-1 patients?

A

Either subtotal parathyroidectomy (3.5 glands) or total parathyroidectomy with autotransplantation

46
Q

How does the surgical approach change for MEN-1 pts vs sporaic ZES pts?

A

MEN-1: image-negative pts should NOT undergo exploration (low cure rates). Non-stage IV Image-positive pts should undergo exploration. All sporadic non-Stage IV ZES should undergo exploration.

47
Q

T/F: Biochemical cure in MEN-1 ZES patients rarely results in a biochemical cure.

A

T. Which is why if the pt has image-negative ZES they should not undergo an exploration

48
Q

If an MEN-1 ZES patient has an image-positive nodule, why should they undergo resection?

A

Because it has been shown to improve survival independent of biochemical cure.

49
Q

Why are data on liver debulking for gastrinomas difficult to make any conclusions regarding treatment?

A

Gastrinoma patients are usually lumped in with neuroendocrine and carcinoid patients.

50
Q

With regards to survival, what is the general consensus for liver resection for metastatic neuroendocrine tumors?

A

5-year survival ranges from 70-100% with liver resection for metastatic neuroendocrine tumors (no % given for pts who did not undergo rsxn)

51
Q

Is there evidence to support liver transplantation for metastatic neuroendocrine tumors?

A

Yes. Should be restricted to pts with primary tumor resected and unresponsive to treatments of metastatic disease (e.g. somatostatin therapy), younger than 50, low Ki67 staining and regular E-cadherin staining.

Cameron Stomach (8 decks)

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