Transcript Typhoid enteritis

Tumors; of the large intestine
I. Benign
A- Adenomatous polyps;
Solitary adenomatous polyp is usually acquired & occurs in patients
over 40 years of age.
Polyps; < 1cm carry 5% risk
2 cm carry 35 – 50 % risk
Macroscopical appearance; pedunculated
& sessile
Microscopical types ; tubular 60 – 80 % , more benign behaviour
Villous 10 % more risk of malignancy
Tubulovillous 10 -20 %
Treatment these lesions have malignant potential &
should be removed as follow:
in pedunculated polyps --- endoscopic removal
if difficult by endoscopic removal
– segmental resection.
Familial adenomatous polyposis of the colon;
This disease is transmitted from both sexes,
males > females.
The adenomatous polyps are most frequently
situated in the
sigmoid colon & rectum,
& often hundreds of tumors are present.
Clinical features;
1. The patient may be asymptomatic or
2. Have lower abdominal pain with loss of weight,
diarrhea, tenesmus & passage of blood &
mucous with stool.
P.R examination --- one or more of the polyps.
Sigmoidoscopy; reveal a variety of neoplasms ranging
from small sessile pink elevations to
pedunculatd tumors.
Barium enema --- will outline large polyps.
Differential diagnosis;
Peutz Jeghers syndrome,
juvenile polyposis,
ulcerative colitis with pseudopoyposis.
Prevention; by
1.
All members of the family should be examined at age
of 10 years & repeated every 2 years.
2.
Those who develop polypi will have them at 20 & these
require operation.
3- If no polypi at age of 20, continue periodic examination
at 5 years intervals till the age of 50. If still no polypi
there is probably no inherited gene.
Treatment ; if operation is possible complete colectomy
is advisable.
The preserved rectum & normal anal sphincter should be
examined regularly for recurrence.
B-Hamartomatous polyps; include
 Peutz-Jegher’s polyps.
 Juvenile or mucous polyps.
These polyps have minimal risk of malignancy
& are only removed if they causing troublesome
bleeding or pain.
C- Hemangiomas;
localized sub-mucosal hemangioma may be
the cause of severe bleeding per rectum,
if the bleeding is continues
both colonoscopy or angiography can help in localizing the bleeding source
& then treated by removal of the lesion if possible
or
by vassopressin + embolization of the feeding artery
or
by segmental resection of the involved segment.
D. Lipomas;
occur less often than in small bowel
& can cause intussusception
or symptoms & signs similar to that
of malignant tumor of large bowel.
II- Malignant tumors;
Carcinoma of the colon;
EPIDEMIOLOGY
The incidence of large bowel cancer varies between and within
countries, which strongly suggests an environmental cause.
3rd cancer in both men & women
In men after prostate , lungs & bronchus
In women after breast, also lungs & bronchus
Incidence in US is 6% ----------- 1/17 male & 1/19 female
90% of cases occur after age of 50 yrs.
The incidence is almost equal between the sexes, with some differences in
risk ratio for cancers of different parts of the large bowel. Rectal
cancers are twice as common among men but for the rest of the large
bowel the male : female ratio is about 0.8 : 1 with right-sided cancers
even more common in women.
There are 2 types;
Hereditary --- F.Hx +ve , young age, presence of other tumors
eg ; FPC , HNPCC
sporadic ---- F.Hx -ve , older age
familial risk increase 3-4 folds for 1st degree relatives, especially if the
patient's age < 50 yr.
It is a good example of the
Fearon-Vogelstein
adenoma-carcinoma multistep Model of carcinogenesis
by
* mutations in tumor suppressor gene
( gate keeper gene ) like APC & P53 & DCC as
initiation .
* mismatch repair genes, ( MMR ) which called
( care taker genes ) that are responsible for
the integrity of genome & correcting DNA replication as
promotion
*oncogens ; proto-oncogenes --- genes that produce proteins
promote growth & proliferation
so over expression lead to neoplasia.
eg; T.G.F-B ( Tissue growth factor – B ) & epidermal G.F, & signal
transducers – ras, spc --- etc.
The Approximate incidence per 100 000
people is mentioned to be
1.
2.
3.
4.
5.
In Africa 2%
In Asia 15%
In South America 15%
In West Europe 40% and
In USA 35%.
Pathology;
Microscopically; it is a columnar cell
carcinoma.
Macroscopically;
The growth usually takes one of the
following forms;
1.
2.
3.
4.
5.
6.
Annular form.
Tubular form.
Ulcerative form.
Cauliflower form.
Multiple primary carcinoma of the colon.
Primary linitis plastica of the colon.
The cauliflower type has the least malignancy.
The annular type has good prognosis not because
of low-grade malignancy but because it give rise
to early obstructive symptoms.
The prognosis also related to the degree of
differentiation of the tumor.
The most frequent site for carcinoma of colon is
the pelvic colon & recto-sigmoid junction.
Spread of carcinoma of colon;
This neoplasm is relatively slowly growing
tumor & if removed thoroughly & at early
stages a cure can be hopefully achieved.
1. Local spread; the growth limited to the
bowel for long time & it spread round the
wall & to a certain extent longitudinally
but usually cause intestinal obstruction
before invading adjacent structures.
2. Lymphatic spread; the lymph nodes
draining the colon are grouped as follow;
1. Epicolic L.Ns. situated in the immediate vicinity
to the bowel wall.
2. Paracolic L.Ns. lying in relation to blood
vessels leashes proceeding to the colonic wall.
3. Intermediate group, they arranged along the
ileocolic, Rt. Colic, middle colic, Lt. Colic &
sigmoidal arteries.
4. The main L.Ns. group; aggregated around the
route of superior & inferior mesenteric vessels.
3- Blood stream spread; metastasis occurs
to the liver by the portal vein & it
accounts for a large proportion 30-40%
of late deaths.
Clinical features;
Carcinoma of colon occurs usually at the
usual age for carcinoma i.e. > 50 year of
age. But it can occur at earlier ages.
25% of cases of carcinoma colon present as
an emergency cases with intestinal
obstruction or peritonitis.
Any patient above 40-yr. Present with
bleeding per rectum a full colonic
examination should be done for him.
There are specific symptoms for carcinoma
of colon at different sites of the colon, for
examples;
1- carcinoma of Lt. Side of colon; in which
75% of cases ca. Colon are situated,
more than 25% of cases are presented
with intestinal obstruction & this is due to
several factors;
1. The neoplasm that situated in the Lt.
Side of the colon is usually of stenosing
type.
2. The fecal contents of the colon are
relatively solid.
3. The lumen of the bowel is comparatively
narrow.
The patient usually presents with pain, which is
colicky in nature, & when it become constant
pain it indicate either inoperability or pericolitis.
The second symptom is alteration in bowel habit in
a previously well & regular bowel movement
patient, the patient says that he experienced an
increased difficulty in passing motion & he take
purgatives for that purpose & some times the
patient complains from alternate constipation &
diarrhea.
Third symptom is palpable mass; very often
the palpable mass is not the tumor itself
but impacted feces above the tumor.
Forth feature is abdominal distension, which
is usually in the lower abdomen & like the
pain is relieved by passing flatus.
2- Carcinoma of sigmoid colon; has the
general features of the Lt. Colonic
cancer, but in addition the patient feels
tenesmus accompanied by passing
mucous & blood with the stool & the
patient feels need for evacuation & may
develop bladder symptoms & some times
develop colovesical fistula.
3- Carcinoma of the transverse colon; this
tumor may be mistaken for carcinoma of
stomach because of it’s position together
with the anemia & weight loss that the
patient may complains from.
4.Carcinoma of caecum & ascending colon;
usually present with
1. Anemia which is severe & difficult to
treat.
2. Mass in the R.I.F.
3. Accidental finding at operation for other
purposes.
4. May be the apex of an intususception.