{"entity":{"id":"colorectal-adenoma-like-adenocarcinoma","kind":"cancer","name":"Adenoma-like adenocarcinoma of the colon and rectum","aka":["Adenoma-like adenocarcinoma of the colon and rectum (invasive cancer that looks like an adenoma on biopsy; better outlook)","Adenoma-like colorectal adenocarcinoma","Villous adenoma-like adenocarcinoma","Invasive papillary adenocarcinoma of the colon"],"tldr":"Adenoma-like adenocarcinoma is a form of bowel cancer whose invasive part still looks like a harmless polyp under the microscope, which is why it is often reported as an adenoma on biopsy and only recognised once the bowel is removed. Despite frequently growing deep into the bowel wall, it spreads to lymph nodes less often than ordinary bowel cancer and does better.","summary":"What it is. The fifth edition of the World Health Organization classification of digestive tumours added adenoma-like adenocarcinoma as a subtype of colorectal adenocarcinoma (Nagtegaal 2020). The invasive component keeps the low-grade villous or tubulovillous architecture and cytology of an adenoma, with pushing rather than infiltrative invasion and little or no desmoplastic stroma, so material taken at endoscopy does not look malignant.\n\nHow it differs from its parent. In a series of 35 such carcinomas, 43 percent had been reported as an adenoma on the preceding biopsy and 60 percent of the resections showed no residual conventional adenoma; despite an advanced T category in 66 percent, only 20 percent had nodal metastases and 15 percent developed distant metastases, and KRAS mutation was frequent (Histopathology 2016). A later review of resected stage I to III colonic adenocarcinomas from one institution classified 91 as adenoma-like, 71 percent of them purely so, and compared them with 251 adenocarcinomas of no special type (Hum Pathol 2021).\n\nHow common it is. Ninety-one tumours against 251 of no special type in the single-institution series above, which is the only published frequency. Because the diagnosis rests on recognising the pattern, it depends on the pathologist and on whether a partial component counts; no national registry records it.\n\nHow it is treated. No trial has been run in this histology. Treated as colorectal adenocarcinoma: resection with adjuvant chemotherapy by stage when removable, the systemic rows of the parent page when not; the parent record carries the trials. The clinically important point is diagnostic rather than therapeutic: a biopsy reported as adenoma in a patient whose scan or endoscopy shows a mass should not close the question, and the possibility of this subtype is the reason why.","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/Colorectal_cancer","links":[{"label":"Nagtegaal, Histopathology 2020: the 2019 WHO classification of tumours of the digestive system","url":"https://doi.org/10.1111/his.13975"},{"label":"Histopathology 2016: adenoma-like adenocarcinoma, a subtype of colorectal carcinoma with good prognosis and deceptive appearance on biopsy (35 tumours)","url":"https://doi.org/10.1111/his.12725"},{"label":"Hum Pathol 2021: adenoma-like adenocarcinoma, clinicopathological characterisation of a newly recognised subtype (91 cases against 251 controls)","url":"https://doi.org/10.1016/j.humpath.2020.09.008"},{"label":"NICE NG151: colorectal cancer, recommendations (Lynch 1.1, local disease 1.3, biomarkers 1.4, metastatic disease 1.5, ongoing care and support including follow-up 1.6)","url":"https://www.nice.org.uk/guidance/ng151/chapter/Recommendations"}],"tags":["gi","colorectal","subtype-page"],"related":["colorectal","colorectal-micropapillary-carcinoma","colorectal-serrated-adenocarcinoma","colorectal-mucinous-adenocarcinoma","colon-cancer","rectal-cancer"],"cancers":[],"sections":[],"technologies":["histopathology-ihc","endoscopy"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["adenoma-carcinoma-sequence","colorectal-polyp-types","tumour-grade","tnm-staging"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"gastrointestinal","burden":"In one American series of resected stage I to III colonic adenocarcinomas from 2013 to 2016, 91 tumours were classified as adenoma-like against 251 of no special type, and 71 percent of the adenoma-like tumours were composed entirely of adenoma-like tissue. No registry count is published.","subtypes":["Pure adenoma-like adenocarcinoma of the colon or rectum (the whole invasive component is adenoma-like; 71 percent of cases in the 2021 series)","Mixed adenoma-like adenocarcinoma of the colon or rectum (more than half but not all of the invasive component is adenoma-like)"],"biomarkers":["Low-grade adenoma-like architecture in the invasive component, recorded in the pathology report","KRAS mutation, frequent in the published series"],"standardOfCare":[{"setting":"Localised disease","approach":"Resection with adjuvant chemotherapy decided by stage as for colorectal adenocarcinoma of no special type; the deceptive biopsy appearance means the diagnosis is often made only on the resection specimen.","refs":["colectomy","capox","folfox","colonoscopy"],"guideline":{"version":"NICE NG151: colorectal cancer (published January 2020, last updated December 2021, last reviewed April 2026)","url":"https://www.nice.org.uk/guidance/ng151"}}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":[],"parent":"colorectal"},"route":"/cancers/colorectal-adenoma-like-adenocarcinoma/","neighbours":{"cancer":[{"id":"colon-cancer","kind":"cancer","name":"Colon cancer (adenocarcinoma of the colon)","route":"/cancers/colon-cancer/"},{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"},{"id":"fap-associated-colorectal-cancer","kind":"cancer","name":"Familial adenomatous polyposis-associated colorectal cancer","route":"/cancers/fap-associated-colorectal-cancer/"},{"id":"colorectal-micropapillary-carcinoma","kind":"cancer","name":"Micropapillary adenocarcinoma of the colon and rectum","route":"/cancers/colorectal-micropapillary-carcinoma/"},{"id":"colorectal-mucinous-adenocarcinoma","kind":"cancer","name":"Mucinous adenocarcinoma of the colon and rectum","route":"/cancers/colorectal-mucinous-adenocarcinoma/"},{"id":"rectal-cancer","kind":"cancer","name":"Rectal cancer","route":"/cancers/rectal-cancer/"},{"id":"colorectal-serrated-adenocarcinoma","kind":"cancer","name":"Serrated adenocarcinoma of the colon and rectum","route":"/cancers/colorectal-serrated-adenocarcinoma/"}],"technology":[{"id":"histopathology-ihc","kind":"technology","name":"Histopathology & immunohistochemistry","route":"/technologies/histopathology-ihc/"}],"term":[{"id":"adenoma-carcinoma-sequence","kind":"term","name":"Adenoma-carcinoma sequence","route":"/terms/adenoma-carcinoma-sequence/"},{"id":"colectomy","kind":"term","name":"Colectomy","route":"/terms/colectomy/"},{"id":"colonoscopy","kind":"term","name":"Colonoscopy","route":"/terms/colonoscopy/"},{"id":"endoscopy","kind":"term","name":"Endoscopy (EGD, EUS, ERCP)","route":"/terms/endoscopy/"},{"id":"tumour-grade","kind":"term","name":"Grade","route":"/terms/tumour-grade/"},{"id":"colorectal-polyp-types","kind":"term","name":"Polyp types in the bowel","route":"/terms/colorectal-polyp-types/"},{"id":"tnm-staging","kind":"term","name":"TNM staging","route":"/terms/tnm-staging/"}],"drug":[{"id":"capox","kind":"drug","name":"CAPOX (capecitabine, oxaliplatin)","route":"/drugs/capox/"},{"id":"folfox","kind":"drug","name":"FOLFOX (5-FU, leucovorin, oxaliplatin)","route":"/drugs/folfox/"}]}}