GI Pathology Flashcards
describe the structure of the oesophagus
lined by squamous mucosa
separated from the submucosa by the muscularis mucosa
deep to this; muscularis propria, with the inner circular and outer longitudinal bundles of smooth muscle
describe the conditions involving oesophageal stenosis
congenital stenosis/atresia; generally paediatric, associated with fistula
thoracic oesophageal malignancy; rarely fistulae into the trachea or one of the main bronchi, frequently leading to mediastinitis and sepsis
achalasia; rare, dysmotility of the distal oesophagus causes dilatation of the proximal oesophagus, can precipitate infection, inflammation and epidermoid metaplasia, can predispose to squamous carcinoma of the oesophagus
liver cirrhosis and elevation of venous pressure in portal venous circulation; engorgement and dilatation of the vascular channel at sites of portal systemic anastomosis, can precipitate oesophageal varices formation
bleeding and haematemesis
describe oesophagitis
most common cause is reflux oesophagitis
cause; regurgitation of the gastric contents into the lower oesophagus
results from incompetence of the lower oesophageal sphincter
symptoms; heartburn, water brash, odynophagia
what are the complications of oesophagitis?
ulceration and necrosis of the squamous epithelial lining; acute inflammation
stricture and stenosis; repeated long-term acute inflammation
fibrosis and structuring; chronic inflammation
Barrett’s metaplasia
describe Barrett’s oesophagus
the stratified squamous epithelial lining is replaced by a columnar epithelial lining/mucosa in the distal 1/3rd of the oesophagus
endoscopy; appears red and velvety vs white native squamous mucosa
can only be detected by endoscopy
histology; squamous mucosa replaced by mate plastic intestinalised columnar mucosa
describe candidal infection of the oesophagus
often seen in immunosuppressed patients; diabetes, HIV, AIDS
endoscopy; raised white plaques
microscopy; fungal hyphae, can be accentuated using periodic acid shift
describe herpes oesophagitis
linear, punched out ulcers within the oesophagus
microscopy; viral infection, multinucleate squamous epithelial cells, containing ground glass viral inclusions
particularly seen in leukaemia and lymphoma
associated with odynophagia
describe eosinophilic oesophagitis
common in young adult males
often present with dysphagia
concentric rings; trachealisation of the oesophagus/feline oesophagus
histology; numerous eosinophils within the squamous epithelium
eosinophilia in the peripheral blood
increased serum try-taste
eosinophilic infiltrates in other parts of the GI tract
describe the different types of cancer of the oesophagus
squamous carcinoma; commonest in middle 1/3, commonest in Asia and Iran
adenocarcinoma; comment in distal 1/3, particularly prevalent in obese middle-aged caucasians
more common in males
what are the risk factors for squamous carcinoma of the oesophagus?
alcohol tobacco dietary nitrosamines types of fungi achalasia genetic predisposition; tylosis
what are the risk factors for adenocarcinoma of the oesophagus?
GORD
obesity/body habitus
barrett’s oesophagus
alcohol/tobacco
what are the patterns of oesophageal cancer?
necrotising malignant ulcer eroding into the wall or adjacent structures
exophytic, polypoid luminal mass
3 diffuse infiltrative neoplasms resulting in stricture
describe Barrett’s metaplasia/oesophagus
a pre-malignant condition
risk factor for oesophageal adenocarcinoma
patients are followed by endoscopic surveillance to detect pre-malignant dysplastic change
what is the treatment of dysplastic Barrett’s tissue?
can be destroyed by an endoscopic procedure
insertion of a radio frequency ablation device and ablating the abnormal mucosa
only destroys to a depth of a few hundred micrometers
insufficient to treat early cancers
describe endoscopic mucosal resection
can treat early Barrett’s related oesophageal adenocarcinoma with a low risk of nodal metastasis
but 90% of oesophageal adenocarcinomas present with advanced disease
describe the staging of oesophageal carcinoma
T1; confined to the innermost layers of the wall
pT1a; intramucosal disease, have not breached the muscularis mucosa
T3; break through the muscularis propria into the surrounding oesophageal adventitial fat
N1 etc; nodal involvement
describe the presentation of oesophageal carcinoma
most common; pT3N1
dysphagia
weight loss
may have occult metastatic disease; PET scan
what is the treatment of oesophageal carcinoma?
dependent on stage
early lesions; endoscopic mucosal resection
more advanced; oesphagectomy
pT3N1; neoadjuvant chemotherapy, then surgery
middle 1/3 tumours and showing squamous morphology; radical chemoradiation
surgically incurable; palliative chemotherapy
HER2 positive; trastuzumab
very unwell; palliative stenting
describe acute erosive gastritis
small punctuate areas of erosion and inflammation in the gastric mucosa
seen in endoscopy
what are the causes of acute erosive gastritis?
NSAIDs iron tables alcohol corrosive substance ingestion systemic chemotherapy uraemia; CKD shock; widespread burns sepsis recent major surgery
what are the types and causes of chronic gastritis?
type A; autoimmune gastritis, associated with pernicious anaemia and lymphocytic infiltrate within the gastric mucosa
type B; chronic active gastritis due to h. pylori infection
type C; distinctive pattern of mucosal injury and regenerative change associated with the exposure of the gastric mucosa to certain types of chemical, NSAIDs, alcohol
most common cause; reflux of bile or duodenal contents
seen sporadically or in previous gastric surgery
describe h. pylori infection
gram negative rod shaped organism
results in chronic active inflammation
secretes urease, breaks down urea to ammonia, resulting in local pH buffering, allowing bacteria to survive
certain strains also produce cytotoxins and incite and inflammatory reaction in the mucosa
can be tested with the ammonia breath test at endoscopy
what are the complications of helicobacter infection?
chronic active gastritis peptic ulcers; gastric and duodenal corpus gland atrophy intestinal metaplasia gastric carcinoma gastric lymphoma
what are the features and complications of peptic ulcers?
haematemesis; coffee grounds
perforation
scarring and stenosis of pylorus; pyloric outlet obstruction
what are the types of gastric carcinoma?
intestinal type
diffuse/poorly cohesive type
describe the intestinal type gastric carcinoma
neoplastic cells form glandular structures that are readily appreciable
particularly prone to lymphovascular invasion and haematogenous spread
more liver metastases seen
describe the diffuse/poorly cohesive type gastric carcinoma
single cell pattern, single dispersed cancer cells infiltrate between and around pre-existing gastric mucosal gland structures
tumour cells adopts a signet ring cell morphology
may diffusely infiltrate and involve the stomach wall
the stomach loses its normal functional ability and becomes rigid
more peritoneal cavity spread; krukenberg tumours
what are the clinical features of gastric carcinoma?
asymptomatic weight loss epigastric mass haematemesis vomiting virchow's node; metastasis to the supraclavicular lymph node
describe krukenberg tumour
spread through the peritoneum to involve the ovaries and give rise to bilateral ovarian metastases
describe the diagnosis and treatment of gastric carcinoma
laparscopy with peritoneal washings; detection of peritoneal metastases
malignant cells in the fluid; contraindication to surgery
removal at primary site is futile if it has spread to the peritoneal cavity
describe gastric lymphoma
longstanding h. pylori chronic gastritis can result in lymphoid follicle formation and accumulation of mucosa associated lymphoid tissue; MALT
antigen-dependent polyclonal reactive lymphoid proliferation
can progress to low-grade lymphoma
what are the histological features of gastric lymphoma?
confluent patterns of growth of the follicles
destruction of the pre-existing native gastric mucosal glands by the formation of lymphoepithelial lesions
associated with monoclonality
what is the treatment of gastric lymphoma?
h. pylori eradication sometimes causes regression of the lymphoid infiltrate
antibiotics
cytotoxic chemotherapies
surgery
conventional lymphoma treatment; spread from another histological type of lymphoma
conventional anti-lymphoma treatment; primary gastric marginal zone lymphoma, primary gastric lymphoma, secondary lymphoma
describe GI stromal tumours
mesenchymal spindle cell tumours
most commonly found in the stomach and the small bowel
dumbbell configuration
sometimes ulceration in relation to the overlying gastric mucosa
seen clearly on CT
difficult to obtain diagnostic preoperative biopsies; ulcer slough
what are the consequences of GI stromal tumours?
mostly small, benign and incidental findings
larger; can be associated with haemorrhage and haematemesis, behave more aggressively
small bowel; more aggressive, behave more malignantly
malignancy; can spread through the peritoneal cavity and develop liver metastases
uncommon to metastasise to local regional lymph nodes
describe CD 117 or c-kit expression of GI stromal tumours
tyrosine kinase gene mutation
susceptible to imatinib (selective TKI)
also show exon 11 of KIT gene mutations
what tumours can affect the small bowel?
adenocarcinoma carcinoid tumours GI stromal tumours malignant lymphoma metastases
describe small bowel adenocarcinoma
less common than primary colonic adenocarcinoma; may be metastatic spread
mostly sporadic
commonly duodenal; napkin ring stricture
associated with crohn’s and coeliac disease
often presents late with poor prognosis
describe duodenal tumours
may be associated with FAP
often polypoid
what are the common sites of primary colonic adenocarcinoma metastases?
small bowel
lung
ovary
breast
describe the grading of carcinoid tumours
1; low-grade malignant tumours, usually primary appendices carcinoids
3; morphological overlap with small cell carcinoma or large cell neuroendocrine
describe carcinoid syndrome
the release of serotonin/5-hydroxytryptamine into the systemic circulation
via the hepatic vein from liver metastases
facial flushing
sweating
wheezing
diarrhoea
long term; endocardial fibrosis in tricuspid and pulmonary valves, associated with RSHF
how is carcinoid syndrome diagnosed?
urinary 5-hydroxyindoleacetic acid (5-HIAA) levels
octreotide or somatostatin scan
what syndromes are carcinoid tumours associated with?
Zollinger-Ellison syndrome; hypergastrinaemia, carcinoid tumour in the 1st part of the duodenum
hypergastrinaemia; peptic ulceration
MEN-1
describe the histological features of carcinoid syndrome
cells with granular eosinophilic cytoplasm
monotonous, low grade features of malignancy
insular or trabecular pattern in a fibrovascular stroma, can sometimes contain amyloid
describe GI stromal tumours of the small bowel
less common
more aggressive
c-KIT mutations; imatinib
exon 9 of KIT gene mutations; implications for blockade of TK with imatinib
describe malignant lymphoma of the small bowel
common site; 25-30% of GI lymphomas
may be primary or secondary
what are the types of malignant lymphoma of the small bowel?
MALToma
Burkitt’s lymphoma
follicular lymphoma
mantle cell lymphoma
enteropathy associated T cell lymphoma (EATL)
post transplant lymphoproliferative disorder
describe MALToma of the small bowel
associated with h. pylori infection
represent a form of low-grade B-cell non-hodgkin’s lymphoma
describe Burkitt’s lymphoma
relatively uncommon high-grade B-cell non-Hodgkin's lymphoma associated with EBV associated with immunosuppression common in children and young adults frequently seen in the terminal ileum very chemo-responsive
describe folicular lymphoma
low-grade B-cell non-hodgkin’s lymphoma
frequently in mesenteric lymph nodes
can occur as a primary neoplasm, particularly within the duodenum
describe mantle cell lymphoma
very strongly associated with the GI tract
usually involves the colon
can form multiple polypoid masses, resulting in multiple lymphomatous polyposis
intermediate grade B-cell lymphoma
describe enteropathy associated T-cell lymphoma (EATL)
aggressive, high-grade, T-cell, non-hodgkin’s lymphoma
very strongly associated with the jejunum and ileum
can be associated with coeliac disease
refractory coeliac disease; prodromal syndrome or a pre-malignant condition
describe post-transplant lymphoproliferative disorders
associated with immunosuppression; treatment of IBD
EBV-driven disorder
most common in renal and other transplants
describe metastases of the small bowel
relatively common
more common that metastases to the large bowel
primary sites; lung, ovary, stomach, breast carcinoma, metastatic melanoma
lobular carcinoma of the breast; most common breast carcinoma that metastasises to the small bowel, also involves the mesentery and retroperitoneum
describe polyps
raised lesion within the lumen of the GI tract
arises within the wall
often pre-malignant
most common types; hyper plastic and adenomatous
hamartomatous polyps; can occur as an inherited polyposis syndrome, Peutz Jeghers syndrome or juvenile polyposis
describe hyperplastic polyps
very common very little malignant potential appear as small polypoid lesions often on the folds of mucosa show serrations; localised hyperplasia of the colonic mucosa
describe adenomatous polyps
very common
dysplastic; indicated an increased risk of malignancy
can range from a few mm to several cm
predominately tubular or villous architecture
what features of a polyp indicate malignancy?
size
degree of dysplasia
type; tubular polyps have a lower risk of dysplasia than those with a villous projection
describe serrated polyps
hydra between the hyperplastic and adenomatous polyp
do not show the same conventional type of dysplastic change that is seen in adenomatous polyps
have pre-malignant potential
describe FAP
AD inheritance
mutation of the APC gene on the long arm of chr 5
growth of many hundreds of adenomatous polyps throughout the large bowel
increased chase of developing colorectal carcinoma
what is the management of carcinoma within the polyp?
invasive adenocarcinoma in a pedunculated polyp; endoscopic snare polypectomy
sessile adenomatous polyps; difficult to remove because of mechanical reasons and because they may be associated within invasion of the wall and earlier spread
what are the identifiable causes of colorectal adenocarcinomas?
10% in total;
5%; HNPCC/Lynch syndrome, results in genetic micro-satellite instability
2%; history of IBD, particularly UC (those with severe UC ~10yrs will have sclerosing cholangitis)
describe the adenoma carcinoma sequence
a morphologically defined progressive sequence of changes associated with tumour development and progression
can be associated with increasing numbers of molecular abnormalities, mutations within tumour suppressor genes and and oncogenes
describe the vogelstein model of the adenoma carcinoma sequence
normal epithelium dysplastic ACF early adenoma late adenoma cancer metastatic cancer
describe the presentation of right-sided colon tumours
iron deficiency anaemia; ulcerating tumour causing blood loss over a prolonged period of time
describe the presentation of left-sided colon tumours
change in bowel habit
crampy abdominal pain
intestinal obstruction; solid stool, thicker wall, smaller lumen
what investigations are required to stage a colorectal cancer?
MRI; rectal cancer staging
CT chest, abdomen and pelvis; nodal status, examine the liver
serum CEA; useful in following the progress of a tumour in patients receiving oncological treatment
what is the treatment of colorectal cancer?
surgery; removal of the segment of bowel affected, associated with the relevant anatomical lymph node drainage groups
adjuvant chemotherapy; to prolong disease-free survival in node positive patients
radiotherapy; primarily for rectal cancer, used prior to surgery or in combination with chemotherapy
describe rectal tumour surgery
mesorectal excision margin; extraperitoneal middle and distal 1/3 of the rectum
all of the tissue is removed en bloc
prevention/reduction of the indigence of local/pelvic recurrence of rectal adenocarcinoma
describe the non-surgical rectal tumour treatment
more bulky and advanced; incomplete tumour resection and recurrence
pre-operative radiotherapy
short course radiotherapy
combination chemotherapy and radiotherapy
long course chemoradiotherapy
