Chapter 17- Small Intestine And Colon Cancers Flashcards
What is the most common neoplastic polyp
Adenoma, which is able to progress to cancer
When are colonic hyperplastic polyps commonly discovered
60/70s
What is the cause of hyperplastic polyps and what is the prognosis
Piling up of goblet cells and parietal cells, but do not have malignant potential
What location are hyperplastic polyps most commonly found
Left colon
What is the histological hallmark of the hyperplastic polyps
Serrated surface architecture
What is the triad of symptoms that lead to the diagnosis of inflammatory polyps
Rectal bleeding, mucus discharge, inflammatory lesion on the anterior rectal wall
What is that cause of inflammatory polyps
Impaired relaxation of the anorectal sphincter leads to a sharp angle of the anterior rectal shelf and leads to abrasion and ulceration
What are the histological hallmarks of an inflammatory polyp
- Mixed Inflammatory infiltrates
- Erosion
- epithelial hyperplasia with fibromuscular hyperplasia
Inflammatory polyps develop as part of which syndrome
Solitary rectal ulcer syndrome
What is the cause of the formation of hamartomatous polyps
Germline mutations in the tumor suppressor genes or protooncogenes
What is the ability of harmartomous polyps to malignancy
There is an increased risk of cancer and they are characterized as pre-malignant
In which patients do the juvenile polyps form
Patients younger than 5
What is the main location of juvenile polyps and how do the typically preset
Rectum and present with rectal bleeding
What are complication of juvenile polyps
- Intussusception
- Intestinal obstruction
- polyp prolapse
Patients with autosomal dominant syndrome of juvenile polyposis commonly have what characteristic of polyps and what is the treatment
Multiple (3 to 100) and must have colectomy to prevent perforation
What are the extraintestinal malformation of juvenile polyposis
Pulmonary arteriovenous malformation and other congenital abnormalities
What are the morphological findings of juvenile polyps
Pedunculated, smooth surfaced, reddish lesions with characteristic cystic spaces after sectioning, usually filled with mucin and inflammatory debris
What is the most common mutation found in juvenile polyps
SMAD4, which codes for the BMPR1A of the TGF pathway
Patients with juvenile polypropsis are most at risk for which condition
Development of colonic adenocarcinoma (30-50% of patients)
What is the clinical presentation of pests-jeghers syndrome
Multiple GI hamartomatous polyps and mucocutaneous hyperpigmentation
What are the characteristics of the mucocutaneous hyperpigmentation seen in Peutz-Jeghers syndrome
Dark blue, brown macules on the lips, nodules, buccal mucosa, hands, genitals and perianal regions
What is the complication seen with Peutz-Jeghers polyps
Can cause intussuseption and multiple malignancies
Which tumors are monitored for in those with Peutz-Jeghers syndrome
- Sex cord tumors of the testes (birth)
- gastric and small intestine cancers (late childhood)
- colon, pancreatic, breast, lung, ovarian, and uterine cancer (20s)
What is the mutation in Peutz-Jeghers
Loss of function mutation in STK11
What is the histological finding in Peutz-Jeghers syndrome
Arborizing network of connective tissue, smooth muscle
What are colorectal adenomas characterized by
Presence of epithelial dysplasia
What are the histological hallmarks for epithelial dysplasia in colon polyps
Nuclear hyperchromasia, elongation, and stratification
How are sessile serrated adenomas secreted from the hyperplastic polyps
Located on the right side of the colon
What are the histological findings of the sessile serrated adenomas
Have malignant potential, but tend to not have the cytological features of dysplasia
-have the serrated architecture through the full length of the glands, including the crypt base, dilation and lateral growth
What are the histological characteristics of the intramucosal carcinoma
Dysplasia epithelial cells breach the membrane to invade the lamina propria
What is the malignant potential of intramucosal carcinoma
Non metastatic because the lymphatic channels are absent in the colonic mucosa
What is the most important characteristic of colorectal adenomas that correlates with malignancy
Size, but there is some with high grade dysplasia
What is the hereditability of Peutz-Jeghers syndrome
Autosomal dominant
What is the hereditability of Familial adenomatous polyposis
Autosomal dominant
Which mutation and pathway is affected in Familial adenomatous polyposis
APC for Wnt pathway
How many polyps are present for Familial adenomatous polyposis tobe diagnosis
At least 100, but may be 1000s
Patients with Familial adenomatous polyposis are guaranteed to get which condition
Colorectal adenocarcinoma
What is the treatment for patients with Familial adenomatous polyposis
Prophylactic colectomy
Despite removal of the colon, patients with Familial adenomatous polyposis develop adenomas in which location
Adjacent to the ampulla of Vater in the stomach
Which extraGI manifestation is commonly seen at birth in patients with Familial adenomatous polyposis
Congenital hypertrophy of the retinal pigment epithelium
What is the condition called when Familial adenomatous polyposis also have a mutation in MYH gene
Autosomal recessive MYH associated polyposis
What are the other names for Hereditary non-polyposis colorectal cancer
HNPCC
Lynch syndrome
What is the most common Syndromic form of colon cancer
HNPCC
In patients that have HNPCC, what cancers are common
Colorectal, endometrium, stomach, ovaries, urease, brain, small bowel, pancreas, and skin
What are the clinical presentations that can give away HNPCC patients
Colon cancers at a younger age and are located on the right side
What is the most common malignancy of the GI tract
Adenocarcinoma of the colon
What is the relative amount of tumors in the small intestine
Very rare
What dietary factors are most related to increased risk of colorectal cancer
Low intake of unabsorbable vegetable fiber and high intake of refined carbs and fat
How do NSAIDs have a protective effect on colorectal cancer development
Inhibition of COX2, which is over-expressed in adenocarcinomas
In colorectal cancer, what is the process of formations with the mutations that are the “hits”
First hit-loss of first APC Second hit-Loss of second APC and beta catenin Subsequent: -Protoonogene mutations in KRAS -TP53 -SMAD
What is the role of APC in the Wnt pathway
Negative regulator of Beta-catenin
Where in the stage of colorectal cancer do mutations in TP53 occur
Late
In patients with DNA mismatch repair deficiency, mutations occur in which areas
Microsatallite instability (MSI)
In colorectal cancers without mutations in DNA mismatch repair, what is commonly seen
CpG island hypermethylation phenotype (CIMP)
In those colorectal cancers with CIMP, what is the promoter region commonly affected
MLH1, with mutations in BRAF region
What are the mutations in the colon cancers with increased CpG methylation wihtoutthe microsatallite instability
KRAS mutation
Invasive carcinomas with microsatellite instability have which characteristics
-Mucinous differentiation and peritumoral lymphocytic infiltrates i the right side of the colon
How can tumors with microsatellite instability be recognized histologically
-Absence of Immuno histological staining for mismatch repair proteins or by molecular genetic analysis of sequences
What is a high risk for patients with HNPCC
Second malignancies of the colon and other organs
What are the characteristics of the adenocarcinomas in the proximal colon
Polyposis, exophytic masses, rarely causing obstruction
What are the characteristics of adenocarcinomas of the distal colon
Annular lesions with “napkin ring lesions” with lumen narrowing
Which location is common to see “napkin ring” and luminal narrowing
Distal colon
What is the clinical appearance of patients with Cecil and right sided colon cancers
Fatigue and weakness due to iron deficiency anemia
What are the clinical presentations of the patients with left sided colon adenocarcinomas
Occult bleeding, bowel habit changes, cramping, and left lower quadrant discomfort
What are the prognostic factors for colorectal cancers
-Depth of invasion and lymph node metastases
What is the most common site of metastasis in colorectal cancers
Liver
What causes condylomata acuminatum
HPV
