lower tract GI tumours Flashcards
where do small intestine adenomas usually occur
ampulla of Vater
may become malignant
where in the small intestine do adenocarcinomas usually occur
duodenum
what do small intestine adenocarcinomas look like
polypoid, exophytic, napkin ring
what are the features of adenocarcinomas of the small intestine
may cause intestinal obstruction
cramping, pain, nausea, vomiting, weight loss, obstructive jaundice,
what is a hamartoma
a benign lesion resembling a neoplasm. grows as a disorganised mass
abnormal tissue in a normal situation
what types of neoplastic adenomas are found in the colon
tubular, villous and tubulvillous
what are hyperplastic polyps
nipple like protrusions of the mucosa
no malignant potentional
what are juvenile polyps
malformations of the mucosa
inflammation
ulceration
non malignant
what is Peutz-Jeghers polyps
autosomal dominant condition
many hamartomatous polyps in digestive tract
increase risk of cancer in other parts of the body
hyperpigementation around the mouth can be used to diagnose
where are adenomas found
intraepithelium
tubular adenomas are most common
how do you asses the risk of a precancerous adenoma becoming an invasive colorectal adenocarcinoma
risk is correlated with: polyp size sessile more likely than tubular histology is essential to determine its clinical significance severity of dysplasia
what do large tubular adenomas look like
coarsely lobulated with slender stalks
what constitutes invasive carcinoma
invasion into the submucosal stalk of the polyp
describe the morphology of villous adenomas
affects older people
commonly in the rectum and sigmoid colon
sessile
velvety or cauliflower like masses projecting above the mucosa
covered by displastic columnar epithelium
invasion may occur directly into the wall of the colon
what are the clinical features of colorectal cancer
may be assymptomatic
maybe:
anaemia
occult or visible blood
when is endoscopic removal of a pedunculated adenoma suitable
the tumour is superficial
there is no vascular or lymphatic invasion
its is well differentiated
sessile polyps are not suitable for polypectomy
what type of tumour do people with FAP have usually
tubular adenomas
what is the most common type of colorectal cancer
adenocarcinoma
what are the risk factors for colorectal cancer
excess calorie intake low vegetable content high refined carbs high red meat decreased micronutrients
where is the most common site of colorectal cancer
rectosigmoid colon
followed by the caecum and ascending colon
what is the morphology of proximal colon tumours
polypoid, exophytic masses
obstruction is uncommon
penetrate the bowel wall as white, firm masses
what is the morphology of distal colon tumours
annular, encircling lesions
ulcerations
narrowed lumen
bowel wall penetration
how might a colorectal cancer be diagnosed
barium enema
or colonoscopy
“apple core lesion”
what is the histology of colorectal cancers
may be differentiated or anaplastic
may produce mucin
stimulates growth of fibrous tissue
what are the signs of colorectal cancer
fatigue, weakness and anaemia
occult bleeding
changes in bowel habit
cramping discomfort
iron deficiency anaemia in an older male = cancer until proven otherwise
systemic symptoms e.g. weight loss and weakness
where might colorectal cancers spread
lymph nodes, liver, lung, bones, serosal membranes, peritoneum, brain
describe Duke’s staging
– A) confined to the submucosa or muscle layer (90+%) – B) spread through the muscle layer, but does not yet involve the lymph nodes (70%) – C) involvinglymph nodes (35%)
what are carcinoid tumours
derived from endocrine cells
half of small intestine tumours
tend to be very slow growing
how do you determine the malignancy of a carcinoid tumour
site of origin
depth of penetration
size of tumour
histological features
what is carcinoid syndrome
the tumour releases hormones which cause symptoms
flushing of the skin
fast heart rate
SOB
diarrhoea, cramps nausea
what are the clinical features of carcinoid tumours
do not metastasize if in the appendix or rectum
90% survival rate
what is GI lymphoma
B-cell lymphoma or T cell lymphoma
what is a leiomyosarcoma
large intramural masses that fungate and ulcerate into the lumen or abdomen
aggressive and rare
mesenchymal
what other mesenchymal tumours can occur
lipomas
leiomyomas
leiomyosarcoma
what are the three zones of the anal canal
the upper (covered with rectal mucosa)
• the middle (partially covered with a transitional mucosa)
• lower (covered by stratified squamous mucosa)
what are the most common benign tumour of the anus
warts
what are some malignant tumours of the anal canal
basal cell carcinoma
squamous cell carcinoma
adenocarcinoma
melanoma
what is the most common type of malignant small intestine tumour
adenocarcinoma and carcinoid
what is the most common type of colorectal cancer
adencarcinoma
what is the most common type of benign small intestine tumour
adenoma
where do adenocarcinomas of the small intestine occur
duodenum - napkin
obstruction
what is the risk of developing an adenocarcinoma before 30 if you have FAP
100%
