Module 2: GI: Gastric Cancer, Gastric Tumors, Meckel's and Malabsorption Syndromes Flashcards
The next topic to discuss is gastric adenocarcinoma. First off what are the two types?
- Intestinal
2. Diffuse
What are features of intestinal gastric adenocarcinoma?
- Much more common than diffuse
- Caused by H. pylori (most common)
- -in the antrum and pylorus - Autoimmune
- -located in the body and fundus - Common in the older men
- Malignant gastric ulcers usually arise de nova (malignant from the get go): following chronic gastritis.
- Pre-disposing factor: dietary – Japanese culture with nitrosamines and nitrites from smoked food
What are features of diffuse gastric adenocarcinoma?
- Much more common in younger females
- Mutation in E cadherin
- Leather bottle stomach on gross: linitis plastic, highly desmoplastic (extensive fibrosis), signet ring cells on biopsy (intracellular metaplasia and PAS stain)
- Complications: Bilateral ovarian metastases called Krukenburg tumors; through seeding of the peritoneal cavity you get direct spread (lymph nodes first)
- Glands: dysplastic or malignant glands invading all layers
What is the presentation for gastric adenocarcinoma?
Early Satiety
Acanthosis nigricans (non specific black neck)
Epigastric Pain
Cachexia
Melena
Enlarged Virchow’s Node
Para Umbilical Subcutaneous Metastasis (called Sister Mary Joseph Nodule)
The best investigation is an Upper GI scope with a biopsy, what would a biopsy show for intestinal?
Malignant glands invading submucosa and muscularis propria
- -secrete mucin if well differentiated in function
- -dysplasia is precursor lesion
On gross image of intestinal, what is the defined factor that it is in fact cancer?
Intestinal:
heaped up margins on gross
–arent seen in benign gastric ulcers
—due to invasion
What are the complications for intestinal adenocaricnoma?
Metastasis to regional lymph nodes
Bleeding – melena — iron deficiency anemia
Obstruction — pyloric – pyloric vomiting
Perforate — peritonitis — sepsis –DIC
What tumor marker is used for both intestinal and diffuse gastric adenocarcinoma?
CEA P CLUBS (Gallbladder cancer)
The next topic to touch on briefly is gastrointestinal stromal tumor (GIST). What are some features?
1 mesenchymal tumor of GI tract
–60% occur in the stomach
Derived from interstitial cells of Cajal (pacemaker cells)
—express CD117 (c-kit) and majority have c-kit mutations in exon 11
What is seen on histology for GIST?
Spindle-shaped tumor cells
What is the treatment for GIST?
Same treatment as chronic myeloid leukemia
Moving onto the Small intestine. The only congenital anomaly to speak about is Meckel’s Diverticulum. What is the pathogenesis?
Due to incomplete involution of the vitelline duct
—congenital true diverticulum (all layers of the bowel) on the anti-mesenteric boarder of the terminal ileum
What is the presentation for Meckel’s Diverticulum?
Asymptomatic
–incidental finding (upon surgery for something else)
What is the rule of 2 in regards to Meckel’s Diverticulum?
2% of the population
2x as common in males
More commonly seen in the first 2 years of life
2 inches long
2 feet from the ileocecal valve
2 tissues (gastric and pancreatic considered choristomas)
What are the complications for Meckel’s Diverticulum?
Acutely inflammed --- fecal obstruction and mimics appendicitis (fever, RLQ pain and elevated WBC due to neutrophilia) Fistula formation (communication b/t two hollow organs) Perforation --peritonitis ---gastric tissue ulceration Bleeding -- iron deficiency anemia