Gastric Neoplasia I Flashcards
What are the main types of non-neoplastic gastric polyps?
Inflammatory/hyperplastic poylps and
fundic gland polyps, which
What are the neoplastic gastric polyps?
Adenomas-precursors to gastric cancer
Describe hyperplastic gastric polyps
These are developed in the presence primarily (60%) in the antrum of the stomach in the chronic gastric inflammation, partially due to H. pylori infection
These are mostly benign, with only a small risk of dysplasia
Most common non-neoplastic polyp
What are these? Describe them
Fundic gland gastric polyps, commonly found in the more proximal (body or fundus) stomach that are usually small (less than 1 cm(, cystic appearing, and clustered on a background of normal, not inflammed stomach
What causes most fundic gland gastric polyps?
These may be sporadic, associated with PPI use, or associated with FAP and rarely have malignant potential unless associated with FAP
Describe gastric adenomas
These are mostly found in the antrum of the stomach and Almost always occur on a background of chronic gastritis with atrophy and intestinal metaplasia.
They are composed of intestinal-type columnar epithelium that exhibits varying degrees of dysplasia, and the risk of malignancy increases with size, villous lesions, and/or high grade dysplasia
T or F. Gastric adenomas are pre-malignant neoplastic lesions with a high risk of transformation to invasive cancer
T. •Like fundic gland polyps, the incidence of adenomas is increased in individuals with FAP.
These need to be removed endoscopically
What pt. pop gets gastric cancer?
More common in lower SC groups and in developing countries with a 2:1 male predominance and an average onset of around 70 yo
NOTE: There is declining incidence in US of distal gastric cancers except in Caucasiasn aged 29-39
What are the main risk factors for gastric cancer?
- Chronic atrophic gastritis
- Pernicious anemia b/c of change in pH
- Prior gastric surgery b/c of change in pH
- High dietary nitrates
- Adenomatous gastric polyps (precursor)
- Smoking and obesity
- Family history gastric cancer-<10 % (Diffuse type)
- Helicobacter pylori infection (Increases risk 3-6 times)
Nitrite is a carcinogen
Notice the continuing trends of decreased incidence of gastric cancer. What are some main reasons why?
1) Tx H. pylori
2) Refrigeration and decreased meat curing/smoking of meat
3) Increase consumption of vegetables
What are some common symptoms associated with gastric cancer?
- diaphragmatic invasions can lead to chronic hiccups
- early perineural invasion can lead to dull pain
- adjacent tissue infiltration can lead to decreased gastric compliance causing early satiety and contributing to weight loss
- Gastric outlet obstruction-distal lesions may obstruct stomach outlet- these will vomit 2-3 hrs after eating
- Ulceration may lead to anemia or hematoemeis and/or melena
Endoscopy is the main way to diagnose. Biopsy needed for distinction between ulcer and malignancy. 6-8 biopsies taken usually
What are the main types of gastric cancer?
90% adenocarcinoma (two types: intestinal and diffuse)
3% lymphoma
0.2% carcinoid
GI stromal tumor (GIST)
What pts is the intestinal type of gastric adenocarcinoma more common in?
males and at older ages
What pts is the diffuse type of gastric adenocarcinoma more common in?
little difference between sexes and more frequent at younger ages
Diffuse may be familial
What is this?
Linitis plastica- a very aggressive diffuse type adenocarcinoma representing around 5% of gastric cancers and marked by transmural infiltration of the gastric wall (poor prognosis) resulting in a rigid, leather-bottle, thickened stomach
Where does gastric cancer usualy MET to?
liver, peritoneum, or distal lymph nodes such as:
left supraclavicular node (aka Virchow’s node)
periumbilical nodule (aka Sister Mary Joseph node)
Staging of gastric cancer is based on what?
depth of infitlration into the gastric wall
NOTE: Even early lesions only carry a 5yr survival of 70%- much worse prognosis than colon cancer
A. Weight loss and anemia suggest cancer
B. More likely to be an adenocarcinoma (lymphoma actually has a better prognosis than adenocarcinoma)
A.
What is this?
A hyperplastic gastric polyp
Micro: Dilated, elongated and tortuous gastric foveolar epithelium with edematous lamina propria containing inflammatory cells
What are these?
Fundic gland gastric polyps
Micro: Cystically dilated lined by flattened parietal and chief cells
How does gastric cancer form?
It is multifactorial with interplay of host and environmental factors. Intially the normal gastric mucosa is subjected to host gene polymorphisms or H. pylori infection which promotes a superficial gastritis, and eventually chronic gastric inflammation exacerbated by a high salt diet or smoking, as well as ROS generation.Chronic inflammation gives rise to atrophic gastritis and eventually metaplasia and dysplasia leading to carcinoma
Adenoma= low grade dysplasia (left)
Right= high grade
What kind of gastric adenocarcinoma is this?
Intestinal type, which tends to form bulky antral (along lesser curvature) masses
What kind of gastric adenocarcinoma is this?
diffuse types, which infiltrates the wall diffusely, thickens it, and is typically composed of signet ring cells
Familial diffuse gastric cancer is strongly associated with germline loss-of-function mutations in the tumor suppressor gene ____, which encodes the cell adhesion protein E-cadherin.
CDH1. 10% of gastric carcinomas are caused by hereditary factors –E-cadherin
Individuals with _____ mutations are at increased risk of developing diffuse gastric cancer.
BRCA2
What is this?
When there are large areas of infiltration involved with a diffuse gastric adenocarcinoma, diffuse rugal flattening and a rigid, thickened wall may impart a leather bottle appearance termed linitis plastica
C.
B would be a mutation in VHL
What kind of gastric cancer is this?
Sporadic type
Sporadic type gastric cancer is associated with what mutations?
These include loss-of-function mutations in the adenomatous polyposis coli (APC) tumor suppressor gene and gain-of-function mutations in the gene encoding β-catenin (Increased signaling via the Wnt pathway)
Sporadic types are associated with APC, K-RAS and Tp53 alterations (AK-53)
NOTE: FAP patients, who carry germline APC mutations, have an increased risk of intestinal-type gastric cancer.
Left: intestinal type gastric carcinoma
Higher-magnification
B. Seeing goblet cells
