Neoplastic Diseases Of The Stomach

Question 1

Gastric polyps

Answer 1

Nodules or masses that project above the level of the surrounding mucosa
- identified rates = 5% roughly

Develops as causes of:
- epithelial and stroma cell hyperplasia

Question 2

Inflammatory/hyperplastic polyps

Answer 2

Roughly 75% of all gastric polyps are inflammatory or hyperplastic
- distinction is made based off degree of inflammation

Most commonly affects people 50=60 yrs of age
- also high incidence when patient has chronic gastritis that initiates injury or during H. Pylori infections

the frequency of these polyps turning into precancerous (dysplastic) polyps is directly proportional to the size of the polyps. >1.5cm = significant risk

Question 3

Fundic gland polyps

Answer 3

Polyps in the fundic glands

• most commonly occur sporadically
• high incidence correlation with familial adeno atoms polyposis (FAP)

Wide spread use of PPIs and NSAIDs also increases the risk of these developing

Question 4

Gastric adenoma

Answer 4

Represent up to 10% of all gastric polyps
- usually occurs in males between the ages of 50-60 yrs

All exhibit epithelial dysplasia
- classified based on low and high grade

Lesions > 2cm in diameter = much more dangerous and have high chance of metastasis

Question 5

Gastric adenocarcinoma

Answer 5

most common malignancy of the stomach and accounts for roughly 90% of all gastric cancers

Early symptoms:

• dyspepsia
• dysphagia
• nausea

Late stage symptoms (usually when diagnosed)

• anorexia
• weight loss
• altered bowel habits
• anemia
• hemorrhage in stool

Question 6

Epidemiology of gastric adenocarcinoma

Answer 6

Vary all over the world

However most common is

• japan
• Chile
• Costa Rica
• Eastern Europe

Question 7

Pathogenesis of gastric adenocarcinoma

Answer 7

Common molecular alterations:

• CDH1: E-cadherin
• APC gene mutations

Loss of E-Cadherin protein, due to methylation of or loss of function mutations in CDH1 is a key step in the development of DIFFUSE gastric cancers

APC gene mutations and FAP diagnosis are key steps in developing SPORADIC intestinal type gastric cancers

BOTH diffuse and sporadic have TP53 mutations

Question 8

How does H. Pylori contribute towards production of gastric adenocarcinomas?

Answer 8

Produces chronic gastritis and chronic inflammation from IL-1B and TNF inflammatory markers
- chronic inflammation causes increased risk of mutations

Question 9

Lauren classification

Answer 9

Separates gastric cancers into intestinal and diffuse types
- depends on gross and histological apperance

Intestinal types = bulky and have a lot of glandular-like structures

Diffuse gastric type = histology: discohesive cells with large mucin vacuoles. “Signet ring” shaped. Gross: shows gross rigid thickening and loss of rugae in the portion of the stomach that has cancer “limitis plastics”

Question 10

Clinical features of gastric adenocarcinomas

Answer 10

Intestinal-type:

• high risks in elderly >55
• higher risks in males
• high risks in japan/Chile/Eastern Europe

Diffuse-gastric type
- there is no epidemiology that increases risks

Early grades on either type = 90% survival rates

Late grades on either type = 20% survival rates

Question 11

Lymphoma

Answer 11

Tumors in the MALT tissues of the GI tract

Most common subtype is Extranodal marginal zone B-cell lymphomas

Question 12

Neuroendocrine (carcinoid) tumors

Answer 12

In the GI tract, arise from Neuroendocrine organs and cells
- most common sites are pancreas tissues and G cells of the stomach as well as 40% of all being found in the small intestine

Question 13

Carcinoid tumor clinical features

Answer 13

Peak incidence = 60s

Symptoms vary based on what endocrine cell/gland is effected and the subsequent overproduction of hormones that follows
- when confined, most hormones are inactivated by first-pass metabolism in liver. Therefore, when symptoms present, it often signifies metastatic cancers

• *carcinoid syndrome: carcinoid tumors that secrete vasoactive substances**
• produces: flushing, sweating, bronchospasms, colicky ab pain, diarrhea, right-sided cardiac fibrosis**

Have three subtypes

• foregut
• midgut
• Hidgut

Question 14

Foregut Neuroendocrine tumors

Answer 14

Found within stomach and proximal duodenum
- rarely metastatic and often can be resected

rarely, gastrinomas can appear in the duodenum and produce symptoms repeated to GERD and Zollinger-Ellison syndrome

Question 15

Midgut Neuroendocrine tumors

Answer 15

Arise in the jejunum and ileum
- are often in multiple Pairs and are highly metastatic

Dont usually produce much symptoms, and if any its broad symptoms of obstruction in the GI tract.
- hence why it’s usually fatal, cant find it fast enough

Question 16

Hindgut Neuroendocrine tumors

Answer 16

Arise in the appendix and colorectum region of the GI tract

Appendix = occurs at any age and almost always benign and asymptomatic

Colorectal = occurs usually in 60s , more dangerous and produce ab pain/weight loss as key symptoms

Question 17

Gastrointestinal stroma tumor (GISTs)

Answer 17

Most common mesenchymal tumor of the abdominal wall
- > 50% are found in the stomach

Shows diffuse spindle cell patterns in stomach mesenchyme

Most common genetic changes in GISTs are gain of function mutations in KIT/CD-1117)

• this is the receptor for stem cell factors
• also 8% present additionally with platelet-derived growth factor receptor A (PDGFRA)

Question 18

Clinical features of GIST

Answer 18

Can be asymptomatic, however the larger they get, the more symptoms will appear

Peak age = 60 yrs
- more common in males

Symptoms:
- similar to esophageal hemorrhages and ulcerations. Also black stools and weight loss

Treatment:

• surgical resection is the primary treatment as long as its localized
• prognosis correlates directly with tumor size/mitotic index and location (low chance of metastasis = <5cm ; high chance of metastasis = >10cm)