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Polyps, DALMs & Megacolon: Polyps, DALMs & Megacolon: Pathology and Imaging of the Colon and RectumPathology and Imaging of the Colon and Rectum
Angela D. Levy and Leslie H. SobinWashington, DC
Drs. Levy and Sobin have indicated that they have no relationships which, in the context of their presentation, could be perceived as a potential conflict of interest.
Polyps, DALMs & MegacolonPolyps, DALMs & MegacolonObjectivesObjectives
1- to present the imaging, classification, and morphology of colorectal polyps
2- to describe DALMs and their significance
3- to present the morphology and imaging of megacolon
Imaging Evaluation of PolypsImaging Evaluation of Polyps
• Epithelial– Sessile – Pedunculated– Filiform
• Subepthelial
CT Colonography: Sessile AdenomaCT Colonography: Sessile Adenoma
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Courtesy of J.R. Choi, Sc.D., M.D.
CT Colonography: Sessile AdenomaCT Colonography: Sessile Adenoma
CT Colonography: Pedunculated AdenomaCT Colonography: Pedunculated Adenoma
CT Colonography: Flat AdenomaCT Colonography: Flat Adenoma
Courtesy of J.R. Choi, Sc.D., M.D.
CT Colonography: Flat AdenomaCT Colonography: Flat Adenoma
Courtesy of J.R. Choi, Sc.D., M.D.
Villous AdenomaVillous Adenoma
Villous AdenomaVillous Adenoma
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Courtesy of J.R. Choi, Sc.D., M.D.
CT CT ColonographyColonography: : AdenocarcinomaAdenocarcinoma
Courtesy of J.R. Choi, Sc.D., M.D.
CT CT ColonographyColonography: : AdenocarcinomaAdenocarcinoma
Annular Annular AdenocarcinomaAdenocarcinoma
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Ulcerative Colitis: Ulcerative Colitis: PseudopolypsPseudopolyps
LipomaLipoma
LipomaLipoma
Rectal Rectal CarcinoidCarcinoid
Rectal GISTRectal GIST
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Intestinal PolypsIntestinal Polyps
• Adenomas• Hyperplastic polyps• Peutz-Jeghers polyps• Juvenile polyps• Inflammatory polyps• Others
Colon: Normal mucosa
Adenoma - subtypes
>20%
Tubular adenoma
Dysplasia starts at the lumen
Tubular adenoma
Villous adenoma
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Sessile Pedunculated
Villous and tubular adenomas
Tubular 71.9%
Tubulovillous22.5%
Villous5.5%
Colorectal adenomas - frequency
Tubular adenoma, low-grade dysplasia
Good nuclear polarity, little mucin reduction, orderly glands
Adenoma, high-grade (severe) dysplasia
Nuclei reach gland surface
Adenoma, high-grade dysplasia (CIS)
Cribriform glands; no invasion beyond mucosa
Colorectal Carcinoma Arising in an Colorectal Carcinoma Arising in an AdenomaAdenoma
• In situ
• Intraepithelial High-grade dysplasia
• Intramucosal
• Invasive = submucosal invasion
[Prevents over-treatment]
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Flat tubular adenoma
No higher than 2x the mucosal thickness
Invasive carcinoma goes to deep margin
Adenocarcinoma arising in a
flat adenoma
Mucin-filled cystic mass in submucosa of polyp’s stalk
Tubular adenoma with pseudoinvasion
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Intestinal PolypsIntestinal Polyps
• Adenomas• Hyperplastic polyps• Serrated polyps• Peutz-Jeghers polyps• Juvenile polyps• Inflammatory polyps
Elongated, straight tubules
Hyperplastic polyp, colon
Serrated adenoma (traditional)
Nuclear stratification of adenoma & serrated profiles of hyp polyp
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Sessile serrated polyp/adenoma
Dilated, horizontal deep glands
Sessile serrated polyp/adenoma
Long >1 cm sessile flat lesion (low power of previous slide)
Sessile Serrated AdenomasSessile Serrated AdenomasHigh risk precursors of microsatellite unstable High risk precursors of microsatellite unstable
colon carcinomascolon carcinomas
• right sided, usually • large, sessile (> 1 cm)• architectural disorder • decreased expression of mismatch repair
proteins: MLH1, MSH2, etc• up to 15% risk of subsequent carcinoma or
high grade dysplasia, esp in rt colon
Genetic PathwaysGenetic Pathways
Tumor suppressor = 85%; Microsatellite = 15% of sporadic adenomas/carcinomas
Serrated PolypsSerrated Polyps
• Hyperplastic polyp • Serrated adenoma (traditional) – localized
lesion; eosinophilic cytoplasm • Sessile serrated adenoma – large, sessile;
disorganized architecture
Sessile ‘adenoma’ rather than sessile ‘polyp’ensures follow-up
Intestinal PolypsIntestinal Polyps
• Adenomas• Hyperplastic polyps• Peutz-Jeghers polyps• Juvenile polyps• Inflammatory polyps
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Peutz-Jeghers polyps
Upright due to muscular infrastructure
Peutz-Jeghers polyp, colon,
Arborizing muscle, little lamina propria, overactive glands
Colon: Peutz-Jeghers polypPeutz-Jeghers polyp, colon
Arborizing muscle, little lamina propria, overactive glands
Peutz-Jeghers polyp, pseudoinvasion, jejunum
Mucosal penetration into muscularis propria
Intestinal PolypsIntestinal Polyps
• Adenomas• Hyperplastic polyps• Peutz-Jeghers polyps• Juvenile polyps• Inflammatory polyps
Juvenile polyp, colon
Round, eroded, expanded lamina propria, cystic dilatation, no muscle, inflamed
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Juvenile polyp (polyposis) - colon
Unusual forms occur in juvenile polyposis, as does dysplasia
Intestinal PolypsIntestinal Polyps
• Adenomas• Hyperplastic polyps• Peutz-Jeghers polyps• Juvenile polyps• Inflammatory polyps
Inflammatory polyp, colon
Granulation tissue polyp
Post-inflammatory polyps (Crohn) - colon
Up-ended mucosa due to ulceration and irregular repair
Post- inflammatory polyps, colon
Result of ulcer healing and repair of up-ended pieces
Post- inflammatory polyps, colon
Mucosa looks healed. Rigidity can cause obstruction
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Post- inflammatory polyps (Crohn)
Rigidity caused obstruction
Ulcerative colitis - pseudopolyps
Ulcerative colitis, pseudopolyps
Mucosal remnants adjacent to ulcers
Inflammatory cloacogenic polyp(Prolapse polyp)
Squamous collar, glandular core, eroded surface
Inflammatory cloacogenic polyp
Pseudomembrane: mucin and polys
Rectum: Mucosal prolapse syndromeColitis cystica profunda
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Intestinal PolypsIntestinal Polyps
• Adenomas• Hyperplastic polyps• Peutz-Jeghers polyps• Juvenile polyps• Inflammatory polyps• Others
Cronkhite-Canada polyp, colon
Gastrointestinal stromal tumor (GIST)
GIST
CD117+
Leiomyoma, colon
Colon:
Lymphomatoid polyposis
Mantle cell lymphoma
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Endometriosis, descending colon polyp:
Ulcerative Colitis Ulcerative Colitis -- Crohn Crohn
Dysplasia Associated Lesion/Mass
(DALM)vs
Adenoma
Ulcerative ColitisUlcerative ColitisDysplasiaDysplasia
• Pedunculated “adenoma” in colitic area + dysplasia-free stalk = adenoma
• Sessile “adenoma” in colitic area = DALM
• Sessile “adenoma” proximal to colitis = adenoma
• Resectable by polypectomy = adenoma
Adenocarcinoma arising in DALM
Low grade dysplasia at surface, invasive carcinoma below
Adenocarcinoma arising in DALM
Low grade dysplasia overlies invasive carcinoma; raised due to invasion
Adenocarcinoma, Crohn colitis
Low-grade tubuloglandular adenocarcinoma
DALM:
Low-grade surface
dysplasia
Invasive carcinoma
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MegacolonMegacolon
• Acute– Common– Transient, secondary to another disease process
• Chronic– Chronic intestinal pseudoobstruction– Chronic intestinal dilatation without obstruction
MegacolonMegacolon• Congenital
– Hirschsprung’s disease• Acquired
– Idopathic– T. cruzi (Chaga’s disease)– Diabetes– Myexdema– Chronic intestinal pseudoobstruction– Toxic megacolon
MegacolonMegacolon
• Imaging evaluation– Typical colonic diameters for diagnosis
• Cecum > 12 cm• Ascending and transverse > 8 cm• Descending and sigmoid > 6 cm
– Radiography• Exclude obstruction
– CT• Wall thickening• Extraintestinal disease
HirschsprungHirschsprung’’s Diseases Disease
HirschsprungHirschsprung’’s Diseases Disease
ChagaChaga’’s Diseases Disease
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Chronic Idiopathic Intestinal Chronic Idiopathic Intestinal PseudoobstructionPseudoobstruction
Hereditary Visceral MyopathyHereditary Visceral Myopathy
Toxic MegacolonToxic Megacolon--Ulcerative ColitisUlcerative Colitis
Toxic MegacolonToxic Megacolon--Ulcerative ColitisUlcerative Colitis
Megacolon