Histopathology 16: Lower GI Flashcards
A 2 year old boy with down syndrome presents with symptoms of constipation with overflow diarrhoea and vomiting. There are signs of abdominal distension. Didnt pass meconium in first 24h of life
What is the most likely diagnosis ?
Hirschsprung’s disease - most common congenital GI abnormality
Where does Volvulus tend to occur in children? Where does it occur in adults ?
Children= small bowel Adults = Sigmoid colon
Which organism causes pseudomembranous colitis ? diagnosis?
C.difficile = antibiotics kill commensal bacteria and allow C.diff to flourish. It’s endotoxins cause Pseudomembranous colitis
TOXIN STOOL ASSAY
List 5 features of Crohn’s disease ?
Transmural inflammation Skip lesions Non-caseating granulomas Cobblestone mucosa Can affect anus to mouth
List 5 features of Ulcerative colitis ?
Involves rectum and Colon but not small bowel
Inflammation confined to the mucosa
Inflammation is continuous, no skip lesions
Backwash ileitis- terminal ileum gets involved
Can cause toxic megacolon
List 3 skin lesions seen in Crohn’s ?
Erythema multiforme
Erythema nodosum
Pyoderma gangrenosum
List 3 familial syndromes characterised by polyps ?
Familial adenomatous polyposis
Peutz-jeghers syndrome
Hereditary non polyposis colorectal cancer (HNPCC)
Name 2 subtypes of FAP ?
Gardner’s syndrome
Turcot syndrome
List 5 extra-intestinal manifestations of Gardner’s syndrome ?
Multiple Osteomas of the skull and mandible
Epidermal cysts
Desmoid tumours
Dental carries/ unerrupted supernumerary teeth
Post surgical mesenteric fibromatoses
List 3 features seen in carcinoid syndrome ?
- Flushing
- Diarrhoea
- Bronchoconstriction / tachycardia
Which test is used to diagnose carcinoid syndrome ?
24 hour urine 5-HIAA
Which paediatric disease presents with up to 100 hamartomatous polyps in children <5 years old ?
Juvenile polyposis
List 3 features of peutz-jeghers syndrome ?
- multiple hamartomatous polyps
- freckles around mouth
- mucocutaenous hyperpigmentation
Which staging system is used to stage colorectal cancer ? describe the stages?
Duke’s staging
A - confined to mucosa
B1 - Extends to muscularis propia
B2 - Transmural invasion
B1 - Extends to muscularis propia + LN INVOLVEMENT
B2 - Transmural invasion + LN INVOLVEMENT
D = Distant Mets
Which tumour marker identifies colorectal cancer ?
CEA
Where does ischaemic colitis occur usually?
watershed zones - supplied by 2 vessels
Splenic flexure + rectosigmoid areas
What are the complications associated w/ UC?
Toxic megacolon
20-30x risk of adenocarcinoma
What are some extra-intestinal manifestations of IBD?
Arthritis Uveitis Stomatitis/ chelitis Pyoderma gangrenosum Erythema nodosum
What are the different polyp types?
Polyps = benign dysplastic lesions that are often precursors to adenocarcinomas
tubular
tubulovillous
villous - greatest risk of malignant transformation
What factors determine the risk of malignant transformation in a polyp?
Polyp type - villous (greatest risk)
Polyp size
Polyp degree of dysplasia
What are colorectal cancers, how common in UK?
98% = adenocarcinomas
2nd most common cancer death in UK
RFs for colorectal cancer?
Low fibre, high fat diet, no exercise, obesity, chronic IBD
What are the inherited lower GI conditions that increase risk of colorectal cancer? inheritance? mx?
FAP
Gardeners syndrome
Hereditary Non-polyposis Colorectal Cancer / Lynch Syndrome
inheritance = AD
mx = MONITORING + TOTAL COLECTOMY
What are the main features of FAP?
Lots of polyps - ~1000
APC tumour suppressor geneonchromosome 5q21
100% will have cancer within 10-15 years
What are the main features of gardeners syndrome?
Subtype of FAP with extra-intestinal manifestations:
Osteomas of the skull and mandible, epidermoid cysts, desmoid tumours, dental caries, unerupted supernumerary teeth
NB QUESTIONS MAY DESCRIBE POOR DENTITION
What are the main features of Hereditary Non-polyposis Colorectal Cancer / Lynch Syndrome (AD)?
Defective DNA mismatch repair
Another extra-colonic cancer at the same time – endometrium, breast, prostate, stomach
VSA1: A 20 year old man was admitted following a 6 day history of diarrhoea, abdominal pain and weight loss. A colon biopsy revealed granulomata.
What is the most likely diagnosis?
Crohn’s Disease
No non-caseating granulomas in ulcerative colitis
VSA2: What is the diagnostic test for C. diff infection?
Toxin stool assay
VSA3: Mutation in which gene is present in Familial Adenomatous Polyposis?
APC (Adenomatous polyposis coli) – tumour suppressor gene
