gastrointestinal_week_4_20190518174147 Flashcards
what is a polyp
protrusion above an epithelial surface - it is a tumour (swelling)
what is malignant epithelial polyps (majority of polyps)
polypod - adenocarcinomas carcinoid polyps
what is majority of benign epithelial polyps
neoplastic - adenoma (do not metastasise)
what is different macroscopic views of polyps
pedunculated (hanging)sessile (slightly raised)flat (completely flat)
why would pedunculated be the polyp youd want
its easier to remove
what does the actual polyp look like under macroscope
irregular surface, long stalk
what does polyp look like histopathologically
dysplastic epithelial lining
what is the different architecture variables of adenoma polyps
tubullovillous, tubular or villousBUT all are dysplastic
what is the consequence of adenomas
they are precursors of cororectal carcinomas
why must all adenomas be removed
because they are all premalignant, either done endoscopically or surgically
what is the pathology of a large bowel tumour
moderately differentiated dirty necrosis patterntumour is invasive through muscularis propia
what is the staging of colorectal carcinoma
dukes A - confined by muscularis propia dukes B - through muscularis propia dukes C - metastatic to lymph nodes
how do patients present with left sided (rectum, sigmoid, descending) colorectal carcinoma - 75%
blood PR, altered bowel habit, obstruction
how do patients present with right sided (caecum, ascending) colorectal carcinoma - 25%
anaemia, weight loss
what is pathology of cororectal carcinoma
varied gross appearance (polypoid, stricturing, ulcerating)typical histopathological appearance (adenocarcinomas)clinical stuff in other lecture
what are the three ways colorectal carcinoma can kill you
local invasion (mesorectum, peritoneum, other organs)lymphatic spread (mesenteric nodes)haematogenous (liver via portal venous system, distant sites)
what are the different kinds of inherited cancer syndromes
heriditary non polyposis coli (HNPCC) - <100 polypsfamilial adenomatous polyposis (FAP) - >100 polypsonly 10% is inherited
what is characteristics of HNPCC
late onset, autosomal dominant, defect in DNA mismatch repair, inherited mutation in MLH-1, MSH-2, PMS-1, MSH-6
what is characteristics of FAP
early onset, autosomal dominant, defect in tumour supression, inherited mutation in FAP gene
how does HNPCC present
right sided tumours, mucinous tumours, crohns like inflammatory response, associated with gastric and endometrial carcinoma
how does FAP present
throughout colon, adenocarcinoma, no specific inflammatory response, associated with desmoid tumours and thyroid carcinoma
the longitudinal smooth muscle layer in caecum and colon is dividd into three strands - what is this called
taeniae coli - it encircles rectum and anal canal smooth muscle is thickened at internal anal sphincter which is surrounded by skeletal muscle of external anal sphincter
the activity of taeniae coli and circular muscle layers in colon causes sac like budges - what is this called
haustra