Tumors of IntestineTumors of Intestiness

IntroductionIntroduction

Overall, colorectal cancer ranks Overall, colorectal cancer ranks second only to bronchogenic second only to bronchogenic carcinoma among the cancer killers. carcinoma among the cancer killers.

Adenocarcinomas constitute the vast Adenocarcinomas constitute the vast majority of colorectal cancers and majority of colorectal cancers and represent 70% of all malignancies represent 70% of all malignancies arising in the gastrointestinal tract.arising in the gastrointestinal tract.

TTerminologyerminology ••A polyp is a tumorous mass that protrudes into A polyp is a tumorous mass that protrudes into

the lumen of the gut; traction on the mass may the lumen of the gut; traction on the mass may create a stalked or pedunculated polyp. create a stalked or pedunculated polyp. Alternatively the polyp may be sessile, without a Alternatively the polyp may be sessile, without a

definable stalk.definable stalk. ••NNon-neoplastic Polyps on-neoplastic Polyps

abnormal mucosal maturation, abnormal mucosal maturation, iinflammationnflammation do not have malignant potentialdo not have malignant potential (excl.Peutz-Jeghers) (excl.Peutz-Jeghers)

••NeoplasticNeoplastic PPolypsolyps:: adenomatous polyps, or adenomasadenomatous polyps, or adenomas,, precursors of carcinoma.precursors of carcinoma.

NNon-neoplastic on-neoplastic (benign) (benign) PolypsPolyps Hyperplastic polypsHyperplastic polyps Hamartomatous polypsHamartomatous polyps

Juvenile polypsJuvenile polyps Peutz-Jeghers polypsPeutz-Jeghers polyps

Inflammatory polypsInflammatory polyps Lymphoid polypsLymphoid polyps

Neoplastic epithelial lesionsNeoplastic epithelial lesions Benign lesions:Benign lesions:

Neoplastic polypNeoplastic polyp AdenomaAdenoma

Malignant lesions:Malignant lesions: AdenocarcinomaAdenocarcinoma Carcinoid tumorCarcinoid tumor Anal zone (anorectal) carcinomaAnal zone (anorectal) carcinoma

Mesenchymal lesions Mesenchymal lesions (benign/malignant)(benign/malignant)

Lymphoma Lymphoma

NNon-neoplastic on-neoplastic (benign) (benign) PolypsPolyps CommonCommon

Hyperplastic polypsHyperplastic polyps AdultsAdults RectosigmoidRectosigmoid MultipleMultiple Nipple-like, Nipple-like, Small protrusions (5 Small protrusions (5

mm)mm) Abundant crypts.Abundant crypts.

Juvenile polyps Juvenile polyps ChildrenChildren RectumRectum Single Single Round massRound mass 1-3 cm1-3 cm Dilated cystic glands.Dilated cystic glands.

Polyps

Hyperplastic polyp

Juvenile polyp

Sessile

Pedunculated

AdenomasAdenomas Small-pedunculated; Small-pedunculated;

large-sessilelarge-sessile ColonColon Familial Familial

predispositionpredisposition Risk of carcinomaRisk of carcinoma Subtypes:Subtypes:

TubularTubular VillousVillous TubulovillousTubulovillous

Malignancy:Malignancy: Rare: tubular Rare: tubular

adenoma less than adenoma less than 1 cm1 cm

High: sessile villous High: sessile villous adenomas more adenomas more than 4 cmthan 4 cm

Dysplasia: villous Dysplasia: villous adenomas. adenomas.

Tubular adenomas:Tubular adenomas: Colon (rectosigmoid)Colon (rectosigmoid) Small-sessile; large-Small-sessile; large-

pedunculatedpedunculated Stalk is covered by Stalk is covered by

normal mucosanormal mucosa Tumor is composed of Tumor is composed of

neoplastic epitheliumneoplastic epithelium Intramucosal Ca or Intramucosal Ca or

invasive Ca.invasive Ca.

Villous adenomas:Villous adenomas: Rectum/rectosigmoidRectum/rectosigmoid Larger than tubularLarger than tubular Sessile Sessile Cauliflower-likeCauliflower-like Dysplasia Dysplasia Ca. Ca.

Tubulovillous Tubulovillous adenomas:adenomas: Peduculated or sessilePeduculated or sessile Mix of tubular and Mix of tubular and

villous patternsvillous patterns DysplasiaDysplasia Malignancy.Malignancy.

Adenoma

Familial polyposis Familial polyposis syndromessyndromes Peutz-JeghersPeutz-Jeghers

SyndromeSyndrome Multiple polyps Multiple polyps

(polyposis coli)(polyposis coli) large, firm polyps with large, firm polyps with

a tree-like structure a tree-like structure distinctive freckles on distinctive freckles on

thethe lips, palms, and lips, palms, and genitalsgenitals

risk for colon cancerrisk for colon cancer.. Turcot's syndromeTurcot's syndrome

Multiple polypsMultiple polyps brain tumors.brain tumors.

Gardner's syndromeGardner's syndrome Multiple polypsMultiple polyps minor birth defects minor birth defects risk for other tumorsrisk for other tumors

((notably mesenchymalnotably mesenchymal).). CowdenCowden's syndrome's syndrome

Multiple polypsMultiple polyps Risk of tumors of:Risk of tumors of:

ThyroidThyroid BreastBreast UterusUterus Skin.Skin.

Part OnePart One

Tumors ofTumors ofSmall IntestineSmall Intestine

Small Intestine tumors:Small Intestine tumors:

Small intestine -75% but tumors – 3-Small intestine -75% but tumors – 3-6%6%

BBenign tumors enign tumors (common)(common) Adenoma(25%), lipoma & leiomyoma.Adenoma(25%), lipoma & leiomyoma.

Malignant tumors Malignant tumors ((rarerare;; <1% <1%)) Adenocarcinoma of Duodenum or Adenocarcinoma of Duodenum or

Jejunum, Carcinoid, Lymphoma, SarcomaJejunum, Carcinoid, Lymphoma, Sarcoma Present at late stage, 70% 5 year Present at late stage, 70% 5 year

survival.survival.

ClassificationClassification Non neoplastic polypsNon neoplastic polyps

Hyperplastic, lymphoid & Hyperplastic, lymphoid & hhamartomatousamartomatous InflammatoryInflammatory

Neoplastic – epithelialNeoplastic – epithelial Benign – AdenomaBenign – Adenoma (ampulla of Vater)(ampulla of Vater) Malignant – Adenocarcinoma, carcinoidMalignant – Adenocarcinoma, carcinoid

Neoplastic – MesenchymalNeoplastic – Mesenchymal Benign - Lipoma, leiomyoma, neuroma, Benign - Lipoma, leiomyoma, neuroma,

angiomaangioma Malignant – Leiomyosarcoma, liposarcoma.Malignant – Leiomyosarcoma, liposarcoma.

LymphomaLymphoma

Benign tumors: LipomaBenign tumors: Lipoma

Most commonMost common Mature adipose Mature adipose

tissuetissue

Adenocarcinoma Adenocarcinoma

Napkin-ring or Napkin-ring or polypoidpolypoid

Duodenum (ampulla Duodenum (ampulla of Vater’s)of Vater’s)

Spreading:Spreading: Regional lymph nodesRegional lymph nodes LiverLiver

Obstructive jaundice.Obstructive jaundice.

Tumors ofTumors ofColon & Colon & RectumRectum

Colorectal carcinomaColorectal carcinoma Adenocarcinomas (98%)Adenocarcinomas (98%) often arises in one of the benign often arises in one of the benign

neoplastic colonic poneoplastic colonic polyplyp risk factorsrisk factors

(1) mild hereditary defects in anti-(1) mild hereditary defects in anti-oncogenes lost in colon cancer, oncogenes lost in colon cancer,

(2) years of eating the typical western diet(2) years of eating the typical western diet.. Low content of vegetablesLow content of vegetables High content of refined carbohydratesHigh content of refined carbohydrates High content of fat (animal)High content of fat (animal) Low content of micronutrients (vitamins A, C, E).Low content of micronutrients (vitamins A, C, E).

MorphologyMorphology Proximal colon tumors:Proximal colon tumors:

polypoidpolypoid Cecum and ascending Cecum and ascending

colon:colon: exophytic exophytic Distal colon:Distal colon: napkin-ring napkin-ring Progression: slow Progression: slow

(years)(years) Types:Types:

Gut: AdenocarcinomaGut: Adenocarcinoma Mucin productionMucin production

Anal zone: Squamous cell Anal zone: Squamous cell carcinomacarcinoma

Spreading:Spreading: Regional lymph nodesRegional lymph nodes LiverLiver

Carcinoid TumorsCarcinoid Tumors 2% of colorectal 2% of colorectal

malignancies.malignancies. Origin:Origin: Neuroendocrine Neuroendocrine

cellscells ( (paracrine, paracrine, Kulchitsky, Kulchitsky, enterochromaffin, enterochromaffin, neurosecretory, neurosecretory, chromaffinchromaffin))

Location:Location: gut gut (common in (common in appendixappendix)) pancreas or peripancreatic pancreas or peripancreatic

tissue, tissue, lungs, lungs, biliary treebiliary tree lliveriver..

Rectal and appendiceal Rectal and appendiceal carcinoidscarcinoids almost neveralmost never metastasizemetastasize

The classic carcinoid The classic carcinoid syndromesyndrome (serotonin) (serotonin) (1) wheezing(1) wheezing (asthmatic) (asthmatic); ; (2) flushing(2) flushing (vasomotor) (vasomotor); ; (3) fibrosis (3) fibrosis (cardiac, (cardiac,

pulmonic, pleural, pulmonic, pleural, pelvic);pelvic);

(4) intestinal (4) intestinal hypermotility.hypermotility.

Midgut carcinoidsMidgut carcinoids:: small intestinal, small intestinal, appendiceal, appendiceal, most colonic most colonic

carcinoids. carcinoids. These are usuallyThese are usually

argyrophil argyrophil ((hormonally activehormonally active).).

Foregut carcinoidsForegut carcinoids:: lung, lung, duodenal,duodenal, biliary carcinoids. biliary carcinoids. These These are almost are almost

never argyrophil never argyrophil (hormonally (hormonally ininactive)active)..

Gastrointestinal Gastrointestinal lymphomalymphoma LLess common than ess common than

carcinomascarcinomas WesternWestern lymphomaslymphomas

are usually familiar are usually familiar B-cell lymphomasB-cell lymphomas

Mediterranean Mediterranean lymphomaslymphomas usually usually feature plasmacytoid feature plasmacytoid differentiationdifferentiation (a (a subset is alpha-subset is alpha-heavy chain heavy chain diseasedisease).).

Sprue-associated Sprue-associated lymphomalymphoma exhibits T- exhibits T-cell markers cell markers

LymphomaLymphoma

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