intestine3 (pathology)

1. Familial polyposis syndrome (FamilialFamilial polyposis syndrome (Familial
adenomatous polyposis)adenomatous polyposis)
CausesCauses
• FAP is caused by a genetic defect.FAP is caused by a genetic defect.
• Polyps usually begin developing during puberty,Polyps usually begin developing during puberty,
and 90% of people with FAP will have polyps byand 90% of people with FAP will have polyps by
age 25.age 25.
• By the age of 40, one or more of these polyps willBy the age of 40, one or more of these polyps will
become cancerous.become cancerous.
Risk FactorsRisk Factors
• The primary risk factor for FAP is having familyThe primary risk factor for FAP is having family
members with this condition.members with this condition.

2. Morphologic and molecular changes in the adenoma-carcinoma
sequence- note the Knudson’s two hit hypothesis

3. Familial polyposis syndrome (FamilialFamilial polyposis syndrome (Familial
adenomatous polyposis)adenomatous polyposis)
1. Familial Polyposis Coli (Large Bowel)1. Familial Polyposis Coli (Large Bowel)
• Large no of neoplastic polyps in the colonLarge no of neoplastic polyps in the colon
• risk of colonic cancer is virtually 100% by midlife,risk of colonic cancer is virtually 100% by midlife,
unless a prophylactic colectomy is performedunless a prophylactic colectomy is performed
Familial colonic
polyposis with
adenocarcinoma

4. 2. Gardner syndrome2. Gardner syndrome
Adenomatous polyps of large bowel associated withAdenomatous polyps of large bowel associated with
one or more of:one or more of:
• multiple osteomas of skull and mandiblemultiple osteomas of skull and mandible
• epidermal cysts of skinepidermal cysts of skin
• soft tissue neoplasms, usually intra-abdominalsoft tissue neoplasms, usually intra-abdominal
3. Turcot syndrome (rare) –3. Turcot syndrome (rare) –
• Colorectal adenomatous polyps associated withColorectal adenomatous polyps associated with
brain tumorsbrain tumors

5. Familial adenomatous polyposis. The surface is
carpeted by innumerable polypoid adenomas

6. Colorectal cancerColorectal cancer
Most ca originate in rectum, rectosigmoid & sigmoidMost ca originate in rectum, rectosigmoid & sigmoid
coloncolon
Risk factorsRisk factors
Diet plays an important roleDiet plays an important role
• Low vegetable fiber content leads to decreasedLow vegetable fiber content leads to decreased
stool bulk & increased faecal transient timestool bulk & increased faecal transient time
• High fat intake leads to increased systhesis ofHigh fat intake leads to increased systhesis of
cholesterol & bile acids by the liver which may becholesterol & bile acids by the liver which may be
converted into carcinogens by intestinal bacteriaconverted into carcinogens by intestinal bacteria
• High content of refined carbohydrates from whichHigh content of refined carbohydrates from which
toxic products are produced which are risk factorstoxic products are produced which are risk factors

7. MorphologyMorphology
Left sided carcinomaLeft sided carcinoma
• Tumors in the proximal colon tend to grow asTumors in the proximal colon tend to grow as
polypoid, exophytic masses without obstructivepolypoid, exophytic masses without obstructive
symptomssymptoms
Righted sided carcinomaRighted sided carcinoma
• Distal colon cancer tend to be annular, encirclingDistal colon cancer tend to be annular, encircling
lesions that produce so-called “napkin-ring”lesions that produce so-called “napkin-ring”
constrictions of the bowel and narrowing of theconstrictions of the bowel and narrowing of the
lumenlumen
• There may be ulcerationThere may be ulceration

8. Cecal carcinoma The exophytic carcinoma projects into the
lumen but has not caused obstruction.

9. Carcinoma of the descending
colon. This circumferential tumor
has heaped-up edges and an
ulcerated central portion. The
arrows identify separate mucosal
polyps

10. HistologyHistology
• Almost all are adenocarcinomas that range fromAlmost all are adenocarcinomas that range from
well-differentiated to undifferentiated, franklywell-differentiated to undifferentiated, frankly
anaplasticanaplastic
• Many tumors produce mucin, which is secretedMany tumors produce mucin, which is secreted
into the gland lumina or into the interstitiuminto the gland lumina or into the interstitium
• Cancers of the anal zone are predominantlyCancers of the anal zone are predominantly
squamous cell in originsquamous cell in origin

11. 1111
The red arrows point to normal crypts.
• The blue arrows point to malignant glands which are
growing both beneath the normal mucosa and on the
right side of the picture up into the mucosa.
• The normal crypts show some technical artifacts

12. Invasive adenocarcinoma of colon showing malignant glands
infiltrating the muscle wall.

13. Clinical featuresClinical features
• Right sided lesions present with fatigue,Right sided lesions present with fatigue,
weakness, and iron deficiency anemiaweakness, and iron deficiency anemia
• Left-sided lesions may produce occult bleeding,Left-sided lesions may produce occult bleeding,
changes in bowel habit, or crampy left lowerchanges in bowel habit, or crampy left lower
quadrant discomfortquadrant discomfort
• the favored sites for metastasis are the regionalthe favored sites for metastasis are the regional
lymph nodes, liver, lungs, and boneslymph nodes, liver, lungs, and bones
• DiagnosisDiagnosis
– digital rectal examinationdigital rectal examination
– fecal testing for occult blood lossfecal testing for occult blood loss
– barium enema,barium enema,
– sigmoidoscopy, and colonoscopy requiresigmoidoscopy, and colonoscopy require
confirmatory biopsyconfirmatory biopsy
– Computed tomography to assess metastaticComputed tomography to assess metastatic
spreadspread
– carcinoembryonic antigen: nonspecific, alsocarcinoembryonic antigen: nonspecific, also
raised in carcinomas of the lung, breast, ovary,raised in carcinomas of the lung, breast, ovary,
urinary bladder, and prostate, as well asurinary bladder, and prostate, as well as
alcoholic cirrhosis, pancreatitis, and ulcerativealcoholic cirrhosis, pancreatitis, and ulcerative
colitiscolitis

14. TNM staging:TNM staging:
• Tumor (T)Tumor (T)
– T0 = none evidentT0 = none evident
– Tis = in situ (limited to mucosa)Tis = in situ (limited to mucosa)
– T1 = invasion of lamina propria or submucosaT1 = invasion of lamina propria or submucosa
– T2 = invasion of muscularis propriaT2 = invasion of muscularis propria
– T3 = invasion through muscularis propria intoT3 = invasion through muscularis propria into
subserosa or nonperitonealized perimuscularsubserosa or nonperitonealized perimuscular
tissuetissue
– T4 = invasion of other organs or structuresT4 = invasion of other organs or structures

15. • Lymph Nodes (N)Lymph Nodes (N)
– 0 = none evident0 = none evident
– 1 = 1 to 3 positive pericolic nodes1 = 1 to 3 positive pericolic nodes
– 2 = 4 or more positive pericolic nodes2 = 4 or more positive pericolic nodes
• 3 = any positive node along a named blood3 = any positive node along a named blood
vesselvessel
• Distant Metastases (M)Distant Metastases (M)
– 0 = none evident0 = none evident
– 1 = any distant metastasis1 = any distant metastasis

16. SpreadSpread
• Local invasion or direct extension into adjacentLocal invasion or direct extension into adjacent
struturesstrutures
• Distant Spread – Metastatis occurs through theDistant Spread – Metastatis occurs through the
lymphatics & blood vesselslymphatics & blood vessels
• Regional lymph nodes, liver, lungs & bones,Regional lymph nodes, liver, lungs & bones,
peritoneum ectperitoneum ect

17. AppendicitisAppendicitis
• Definition -Definition - Acute inflammation of the appendix,Acute inflammation of the appendix,
AetiologyAetiology
Exact cause is unknown. Contributory factors areExact cause is unknown. Contributory factors are
• Age – mostly less than 10 years & adolescentAge – mostly less than 10 years & adolescent
A. Obstructive agentsA. Obstructive agents
1. In Lumen of appendix –1. In Lumen of appendix –
• FaecolithFaecolith
• Threadworm or round wormThreadworm or round worm
• Foreign bodyForeign body
• True calculus, gallstoneTrue calculus, gallstone
Dr S ChakradharDr S Chakradhar 1717

18. AppendixAppendix
normal:normal:

19. 2. in the wall2. in the wall
• Hyperplasia of lymphoid tissueHyperplasia of lymphoid tissue
• Extension of tumour of caecum, or primary tumorExtension of tumour of caecum, or primary tumor
of appendixof appendix
3. Outside the wall3. Outside the wall
• Compression by bands, adhesionCompression by bands, adhesion
Mixed infectionMixed infection
• with E Coli (85%A), enterococci, clostridiumwith E Coli (85%A), enterococci, clostridium
perfringes & bacteroids are formed in inflammaedperfringes & bacteroids are formed in inflammaed
appendixappendix
1919

20. PathogenesisPathogenesis
According to obstruction to lumenAccording to obstruction to lumen
• Non obstructiveNon obstructive
• ObstructiveObstructive
Non ObstructiveNon Obstructive
Sequelae may beSequelae may be
• ResolutionResolution
• UlcerationUlceration
• SuppurationSuppuration
• Gangrene of the tip due to arterial occlusion byGangrene of the tip due to arterial occlusion by
inflammation or thrombosisinflammation or thrombosis
• FibrosisFibrosis
Dr S ChakradharDr S Chakradhar 2020

21. ObstructiveObstructive
• After obstruction, continuing secretion increasesAfter obstruction, continuing secretion increases
intra luminal pressureintra luminal pressure
• which causes collapse of veins & ischemic injurywhich causes collapse of veins & ischemic injury
• followed by bacterial invasionfollowed by bacterial invasion
• ischemic and septic necrosis,ischemic and septic necrosis,
Gangrene or perforation is more common & rapidGangrene or perforation is more common & rapid
2121

22. MorphologyMorphology
1. Early acute appendicitis1. Early acute appendicitis
GrossGross
• Congestion. Serosa is read in appearanceCongestion. Serosa is read in appearance
(dilatation)(dilatation)
MicroMicro
• Scanty neutrophil exudation throughout the mucosa,Scanty neutrophil exudation throughout the mucosa,
submucosa & muscularissubmucosa & muscularis
2222

23. 2. Acute diffuse suppurative appendicitis (later2. Acute diffuse suppurative appendicitis (later
stage )stage )
GrossGross
• Dilated lumen, thickened wall, dusky discoloration ofDilated lumen, thickened wall, dusky discoloration of
serosa,serosa,
• fibrinous or fibrinopurulent serosal exudatefibrinous or fibrinopurulent serosal exudate
MicroMicro
• Marked neutrophil infiltration if the entire wallMarked neutrophil infiltration if the entire wall
• There may be abscess formation & ulceration ofThere may be abscess formation & ulceration of
mucosamucosa
2323

24. 2424
•Granular roughened serosa
with marked congestion at tip
(yellow arrow)
•Grey yellow purulent exudate
on the surface (green arrows)
•Marked increase in diameter
•The cross sectioned end
appears dilated and the wall
appears thickened and
edematous
•The serosa is congested with
yellow plaques of exudate
(arrow)
•The serosal surface of the
intact appendix shows

25. C.Acute gangrenous appendicitisC.Acute gangrenous appendicitis
GrossGross
• Distal part or large areas become gangrenous &Distal part or large areas become gangrenous &
looks blacklooks black
• It may ruptureIt may rupture
MicroMicro
• The histological picture of Extensive necrosis ofThe histological picture of Extensive necrosis of
mucosa and muscularis, with microabscesses withinmucosa and muscularis, with microabscesses within
the appendiceal wallthe appendiceal wall
2525Rupture of appendix secondary
to transmural acute
appendicitis.
0
5 0
1 0 0
第 一 季 度 第 四 季 度
东 部
西 部
北 部

26. 2626
Area of acute necrosis within
the wall of the appendix in the
setting of acute appendicitis.
The mucosa on the left is
totally necrotic and infiltrated
by polys in contrast to the
normal viable mucosa on the
right which shows no necrosis

27. Acute appendicitisAcute appendicitis
• Loss of continuity of mucosal lining in someLoss of continuity of mucosal lining in some
places indicating mucosal ulceration or sloughingplaces indicating mucosal ulceration or sloughing
• Infiltration of acute inflammatory cellsInfiltration of acute inflammatory cells
(polymorphs) in all layers including muscle coats(polymorphs) in all layers including muscle coats
• The lumen also contains inflammatory exudateThe lumen also contains inflammatory exudate
Dr S ChakradharDr S Chakradhar 2727

28. 2828

29. 2929

30. 4 major causes of bowel obstruction

31. Hernia – InguinalHernia – Inguinal

32. Diverticulosis :
• protrusion of mucosa and submucosa through the
muscle wall.

33. IntussusceptionIntussusception

34. Volvulus:Volvulus:

35. 3535
A) which is superior the appendix. CT
image “B” is distal to the ileocecal
junction. It shows a swollen appendix
due to acute appendicitis. The appendix
is easier to see because it is fluid filled.
This axial slice also demonstrates the
location of the appendix, which is
posteromedial in this patient and about
2.5 cm below the ileocecal junction.

36. 3636

37. 3737