Adenomatous polyps are a common type. They are gland-like growths that develop on the mucous membrane that lines the large intestine.YouAreHere:Home→MedicalEncyclopedia→ColorectalpolypsURLofthispage://medlineplus.gov/ency/article/000266.htmColorectalpolypsAcolorectalpolypisagrowthontheliningofthecolonorrectum.CausesPolypsofthecolonandrectumaremostoftenbenign.Thismeanstheyarenotacancer.Youmayhaveoneormanypolyps.Theybecomemorecommonwithage.Therearemanytypesofpolyps.Adenomatouspolypsareacommontype.Theyaregland-likegrowthsthatdeveloponthemucousmembranethatlinesthelargeintestine.Theyarealsocalledadenomasandaremostoftenoneofthefollowing:Tubularpolyp,whichprotrudesoutinthelumen(openspace)ofthecolonVillousadenoma,whichissometimesflatandspreading,andismorelikelytobecomeacancerWhenadenomasbecomecancerous,theyareknownasadenocarcinomas.Adenocarcinomasarecancersthatoriginateinglandulartissuecells.Adenocarcinomaisthemostcommontypeofcolorectalcancer.Othertypesofpolypsare:Hyperplasticpolyps,whichrarely,ifever,developintocancerSerratedpolyps,whicharelesscommon,butmaydevelopintocancerovertimePolypsbiggerthan1centimeter(cm)haveahighercancerriskthanpolypssmallerthan1centimeter.Riskfactorsinclude:AgeFamilyhistoryofcoloncancerorpolypsAtypeofpolypcalledvillousadenomaAsmallnumberofpeoplewithpolypsmayalsobelinkedtosomeinheriteddisorders,including:Familialadenomatouspolyposis(FAP)Gardnersyndrome(atypeofFAP)Juvenilepolyposis(diseasethatcausesmanybenigngrowthsintheintestine,usuallybefore20yearsold)Lynchsyndrome(HNPCC,adiseasethatraisesthechanceofmanytypesofcancer,includingintheintestine)Peutz-Jegherssyndrome(diseasethatcausesintestinalpolyps,usuallyinthesmallintestineandusuallybenign)SymptomsPolypsusuallydonothavesymptoms.Whenpresent,symptomsmayinclude:BloodinthestoolsChangeinbowelhabitFatiguecausedbylosingbloodovertimeExamsandTestsYourhealthcareproviderwillperformaphysicalexam.Alargepolypintherectummaybefeltduringarectalexam.Mostpolypsarefoundwiththefollowingtests:Bariumenema(rarelydone)Colon