tumors of small bowel Flashcards
(23 cards)
What are the common demographic characteristics of benign small intestinal tumors?
Both sexes equally affected, peak incidence in the sixth decade, most tumors are asymptomatic.
What are Gastrointestinal Stromal Tumors (GISTs) and their origin?
Tumors arising from interstitial cells of Cajal.
How are GISTs diagnosed?
By c-kit proto-oncogene protein (CD117) through immunohistochemical tests.
What features distinguish benign GISTs from malignant ones?
Benign GISTs show fewer mitoses, are generally smaller, and lack necrosis, nuclear pleomorphism, and invasive/metastatic behavior.
Name some other nonepithelial benign small bowel lesions.
Lipomas, hemangiomas, hamartomas, lymphangiomas, neurogenic tumors (schwannomas, neurofibromas).
What are the common locations for lipomas in the small intestine?
Duodenum and ileum.
What percentage of benign small bowel lesions are hemangiomas, and what syndrome are they associated with?
5%, and they are associated with Osler-Weber-Rendu syndrome.
What is the significance of capsule enteroscopy and angiography for hemangiomas?
Capsule enteroscopy helps delineate hemangiomas, and angiography is useful for actively bleeding lesions.
What is Peutz-Jeghers syndrome and its associated features?
An autosomal dominant trait associated with multiple hamartomas and mucocutaneous hyperpigmentation.
Where do tubular adenomas most commonly occur, and are they usually symptomatic?
In the duodenum, and they are usually asymptomatic.
Why should villous adenomas be excised?
They have a higher risk of harboring malignancy (30% risk, increasing with size).
What complications can arise from benign small bowel tumors as they enlarge?
Obstruction, intussusception, GI bleeding, palpable abdominal mass, intra-abdominal bleeding, or perforation.
How common are malignant small intestinal tumors, and who is most affected?
They constitute only 2% of all GI tract malignancies, slightly more common in males, average age in the sixth decade.
What is the most common location for small intestinal adenocarcinomas?
The duodenum.
What are common presentations of small intestinal adenocarcinomas?
Obstruction (often with weight loss), occult bleeding, anemia, and painless jaundice in periampullary lesions.
What is the prognosis for small intestinal adenocarcinomas after surgical intervention?
Poor 5-year survival (10%-30%).
From what cells do carcinoid tumors arise?
Kulchitsky cells in crypts of Lieberkuhn (amine precursor uptake and decarboxylation system).
What is the most common site for small intestinal carcinoid tumors?
The ileum.
What is carcinoid syndrome, and how is it diagnosed?
A complex of symptoms (flushing, bronchospasm, cramping, diarrhea, etc.) related to serotonin production by the tumor, diagnosed by urinary 5-HIAA and serum serotonin or chromogranin A.
What is the most common site for extranodal lymphoma in the small intestine?
The ileum (Peyer’s patches).
How is small intestinal lymphoma commonly treated?
Chemotherapy and sometimes radiation, with surgical resection for emergencies.
What are GISTs and their treatment options?
Mesenchymal tumors exhibiting c-kit protein expression, treated with wide excision and tyrosine kinase inhibitors (e.g., imatinib).
What is the importance of high-risk surveillance in individuals with familial polyposis?
Regular endoscopic surveillance of the duodenum and papilla to detect duodenal carcinoma of the periampullary region early, which arises from preexisting benign adenomas.
