Chapter 087. Gastrointestinal Tract Cancer (Part 8)

Table 87-5 Hereditable (Autosomal Dominant) Gastrointestinal Polyposis SyndromesSyndrom eDistribuHistolo nantMaligAssociated Lesionstion of Polyps gic TypePotentialFamilial adenomatous polyposisLarge intestine aAdenom onCommNoneGardnersLargeAdenomCommOsteomas,syndromeand intestinessmall aonfibromas, lipomas, epidermoid cysts, ampullary cancers, congenital hypertrophy retinal ofpigmentepitheliumTurcots syndromeLarge intestine aAdenom onComm tumorsBrainNonpolyLargeAdenom onComm alEndometri and ovarianposis syndrome intestine (often a (Lynch syndrome) proximal)tumorsPeutzJeghers syndrome andSmall large omaHamartRare eousMucocutanintestines,pigmentation;stomachtumors ovary, pancreas,ofthebreast,endometriumJuvenile polyposis andLarge small oma,Hamart rarelyRare ...
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Chapter 087. Gastrointestinal Tract Cancer (Part 8) Chapter 087. Gastrointestinal Tract Cancer (Part 8) Table 87-5 Hereditable (Autosomal Dominant) GastrointestinalPolyposis Syndromes Syndrom Distribu Histolo Malig Associatede tion of Polyps gic Type nant Lesions Potential Familial Large Adenom Comm Noneadenomatous intestine a onpolyposis Gardners Large Adenom Comm Osteomas,syndrome and small a on fibromas, intestines lipomas, epidermoid cysts, ampullary cancers, congenital hypertrophy of retinal pigment epithelium Turcots Large Adenom Comm Brainsyndrome intestine a on tumors Nonpoly Large Adenom Comm Endometriposis syndrome intestine (often a on al and ovarian(Lynch proximal) tumorssyndrome) Peutz- Small Hamart Rare MucocutanJeghers and large oma eoussyndrome intestines, pigmentation; stomach tumors of the ovary, breast, pancreas, endometrium Juvenile Large Hamart Rare Variouspolyposis and small oma, rarely congenital intestines, progressing to abnormalities stomach adenoma Polyposis Coli Polyposis coli (familial polyposis of the colon) is a rare conditioncharacterized by the appearance of thousands of adenomatous polyps throughoutthe large bowel. It is transmitted as an autosomal dominant trait; the occasionalpatient with no family history probably developed the condition due to aspontaneous mutation. Polyposis coli is associated with a deletion in the long armof chromosome 5 [including the APC (adenomatous polyposis coli) gene] in bothneoplastic (somatic mutation) and normal (germline mutation) cells. The loss ofthis genetic material (i.e., allelic loss) results in the absence of tumor-suppressorgenes whose protein products would normally inhibit neoplastic growth. Thepresence of soft tissue and bony tumors, congenital hypertrophy of the retinalpigment epithelium, mesenteric desmoid tumors, and ampullary cancers inaddition to the colonic polyps characterizes a subset of polyposis coli known asGardners syndrome. The appearance of malignant tumors of the central nervoussystem accompanying polyposis coli defines Turcots syndrome. The colonicpolyps in all these conditions are rarely present before puberty but are generallyevident in affected individuals by age 25. If the polyposis is not treated surgically,colorectal cancer will develop in almost all patients before age 40. Polyposis coliresults from a defect in the colonic mucosa, leading to an abnormal proliferativepattern and impaired DNA repair mechanisms. Once the multiple polyps aredetected, patients should undergo a total colectomy. The ileoanal anastomotictechnique allows removal of the entire bowel while retaining the anal sphincter.Medical therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) such assulindac and cyclooxygenase-2 inhibitors such as celecoxib can decrease thenumber and size of polyps in patients with polyposis coli; however, this effect onpolyps is only temporary, and NSAIDs are not proven to reduce the risk of cancer.Colectomy remains the primary therapy/prevention. The offspring of patients withpolyposis coli, who often are prepubertal when the diagnosis is made in the parent,have a 50% risk for developing this premalignant disorder and ...