GIT 5 Flashcards
(8 cards)
What are the pathological features of ulcerative colitis (UC) grossly?
Grossly, ulcerative colitis is a diffuse lesion. The involved colonic mucosa may be slightly erythematous and granular or have extensive, broad-based ulcers. Pseudopolyp formation occurs due to regenerating mucosal islands between areas of ulceration. The serosa is normal. A rare complication is toxic megacolon, which involves prominent dilation and thinning of the colonic wall.
What are the microscopic features of ulcerative colitis?
Microscopically, ulcerative colitis shows diffuse lymphoplasmacytic inflammation in the lamina propria, cryptitis and crypt abscesses, and mucosal ulceration extending into the submucosa. Granulomas are not present in UC.
What are the key differences between Crohn disease (CD) and ulcerative colitis (UC)?
• Crohn disease can affect any part of the GIT, mainly the terminal ileum, while UC always involves the rectum and part or the entire colon.
• CD shows transmural inflammation, deep ulcers, and a thick bowel wall, whereas UC involves mucosal and submucosal inflammation, superficial ulceration, and a thin bowel wall.
• Skip lesions are present in CD but absent in UC.
• Granulomas are common in CD but absent in UC.
• Fistula and stenosis are common complications in CD but rare in UC.
• UC has a higher risk of malignancy compared to CD.
What are the types of non-neoplastic polyps?
Non-neoplastic polyps include:
1. Hamartomatous polyps:
◦ Juvenile polyps: Commonly found in children younger than age 5, usually solitary, and located in the rectum.
◦ Peutz-Jeghers polyps: Large polyps with an arborizing network of smooth muscle and glands lined by normal-appearing intestinal epithelium.
2. Inflammatory polyps: Form as a result of chronic cycles of injury and healing, seen in inflammatory diseases of the large bowel.
3. Hyperplastic polyps: Most commonly found in the left colon, typically less than 5 mm in diameter, with a serrated surface architecture and a sawtooth appearance.
What are the types of neoplastic polyps (adenomas)?
Neoplastic polyps (adenomas) are classified into:
1. Tubular adenomas: Tend to be small, pedunculated polyps with a stalk covered by normal colonic mucosa and a head composed of neoplastic epithelium forming branching rounded or tubular glands.
2. Villous adenomas: Often large and sessile, composed of numerous finger-like projections of epithelium.
3. Tubulovillous adenomas: Features of both tubular and villous adenomas.
What factors increase the risk of malignant transformation in adenomas?
The risk of malignant transformation in adenomas is correlated with:
• Size: The larger the size, the greater the risk (most significant).
• Histological type: Villous adenomas have a higher risk.
• Dysplasia: Severe dysplasia increases the risk.
• Number: An increase in the number of polyps increases the risk.
What is Familial Adenomatous Polyposis (FAP), and what is its risk of malignancy?
Familial Adenomatous Polyposis (FAP) is an autosomal dominant disease caused by a genetic defect in the APC gene. A minimum of 100 adenomas are required for diagnosis. It is evident in adolescence or early adulthood, and the risk of colonic cancer is 100% by midlife unless a prophylactic colectomy is performed.
What is Peutz-Jeghers syndrome, and what are its characteristics?
Peutz-Jeghers syndrome is a rare autosomal dominant condition characterized by pigmentation around the mouth and oral cavity, with multiple polyps in the small intestine. These polyps rarely undergo malignant transformation.
