Chapter 13: GI Colon and Rectal Cancers Flashcards
During routine colonoscopy, a protruding mass is discovered. It is removed and examined (below).
Adenomatous polyp: This one is tubular.
Tubular: Smooth surfaced lesions, often have a stalk. Closely packed epithelial tubules embedded in a fibrovascular stroma. Carcinoma risk depends on size.
During routine colonoscopy, a protruding mass is found. It is removed and examined.
Villous adenoma: Large, broad-based, elevated lesions with shaggy, cauliflower-like surfaces. Composed of thin, tall, finger-like processes. Supported by fibrovascular connective tissue core. More frequently contain carcinoma foci.
Tubulovillous: Intermediate in form between tubular and villous.
Other variants: Villous and tubulovillous.
A small, sessile, mucosal protrusion with exaggerated crypt architecture is discovered in a patient undergoing routine endoscopy.
Hyperplastic polyp.
Crypts are elongated and may show cystic dilation. Epithelium contains goblet cells and absorptive cells with no dysplasia. “Sawtooth appearance”.
Serrated adenoma, sessile serrated adenoma, mixed hyperplastic adenomatous polyps
A patient undergoing first time colonoscopy is surprised to learn that you found hundreds of adenomas carpeting the colorectal mucosa.
Mostly tubular adenomas.
Familial adenomatous polyposis. Autosomal dominant mutation in the APC gene.
Hundreds to thousands of adenomas carpeting the colorectal mucosa.
Carcinoma of the colon and rectum is inevitable. Must perform total colectomy.
Attenuated FAP: Adenomas number < 100
Gardner syndrome: Extracolonic lesions - osteomas of skull, mandible, long bones. Cysts.
Turcot syndrome: FAP with malignant tumors of CNS. Medulloblastoma. HNPCC syndrome.
A 5 year old child presents with a colonic polyp. On biopsy, the polyp has a smooth rounded surface and contains cystically dilated glands filled with mucus.
Juvenile polyps. Hamartomatous proliferations of the colonic mucosa.
Multiple polyps: Syndrome of familial juvenile polyposis - mutation in SMAD4. TGF-beta signaling pathway mutation. Increased risk for GI carcinoma.
A patient presents with an elevated nodule of inflamed, regenerating epithelium.
Commonly found with ulcerative colitis and Crohn disease, and amebic colitis and bacterial dysentery.
Inflammatory polyp.
As healing proceeds, epithelial regeneration characterized by large, basophilic epithelial cells restores mucosal architecture.
A patient presents with a single, sessile, submucosal accumulation of lymphoid tissue.
Lymphoid polyp.
Multiple leasions can impart a cobblestone appearance. Benign, asymptomatic.
Nodular lymphoid hyperplasia: Seen in children or with common variable immunodeficiency syndrome. Numerous small sessile or polypoid nodules that resemble lymphoid polyps.
What are risk factors for colorectal cancer?
Adenomatous polyps.
Dietary fat
Anaerobic bacteria (bacteriodes)
Dietary fiber
Other dietary factors (serotonin bad, glutathione peroxidase good)
APC gene mutation (tumor suppressor gene, negatve regulator of beta-catenin, activates cyclin D1 and MYC). -> Ras -> DCC -> p53. MMR.
Age
Prior colorectal cancer
Ulcerative colitis and Crohn disease
A patient presents with bright red blood and iron deficiency anemia. A biopsy is taken and shows the following.
Colorectal adenocarcinoma.
Left: Ulcerated mass with enlarged, firm, rolled borders.
Right: Resembles moderately differentiated glands with prominent cribiform pattern and central necrosis.
A patient is found with a mass with a high frequency of mucinous signet ring cells, solid histologies, and frequent intratumoral lymphocytes.
He has a family history of young-onset cancer, tumors proximal to the splenic flexure, and extracolonic cancers (endometrium, ovary, stomach, small intestine, hepatobiliary tract, transitional cell carcinoma of renal pelvis and ureter).
Few adenomas.
Multiple synchronous or metachronous colorectal cancers.
Hereditary nonpolyposis colorectal cancer (HNPCC). AKA Warthin-Lynch syndrome.
Autosomal dominant inherited disease, germline mutations in DNA mismatch repair genes.
Large bowel lymphoma is usually…
B-cell malignancy.
Cancers of the anal canal are mostly…
Epidermoid carcinomas.
Can be squamous, basaloid (cloacogenic) or mucoepidermoid.
Bowen disease of the anus: SCC in situ
Extramammary Paget disease: Intraepithelial adenocarcinoma
