intestinal polyposis - Wael Fathy

Document Sample
intestinal polyposis - Wael Fathy Powered By Docstoc
					By assistant lecturer : Wael Fathy
  Small intestinal polyps may be present as a part of hereditary
gastrointestnal plyposis syndromes or small intestinal neoplasia .


Hereditary gastrointestnal plyposis syndromes as :

    Familial Adenomatous Polyposis
    Gardner's Syndrome

    Peutz-Jeghers syndrome
   Juvenile Polyposis
   Cowden's Disease
   Neurofibromatosis
Familial Adenomatous Polyposis
   Familial Adenomatous Polyposis has an autosomal dominant mode
 of inheritance and is the most common adenomatous polyposis
 syndrome.

 The frequency of its gene has been estimated on the basis of
 disease prevalence to be 1 in 5000 to 1 in 7500 .

 It is characterized by the presence of hundreds or thousands of
 adenomatous polyps throughout intestine.

 The polyps are typically less than one centimeter in diameter,
 and they may be either sessile or pedunculated with tubular,
 tubulovillous or villous histologic features.

  Nearly 80 percent of the patients with familial adenomatous
  polyposis have colorectal cancer.
  Extracolonic features are now recognized with varying frequency
in patients with familial adenomatous polyposis. Among these
features mandibular osteomas, which may be multiple.


  Nearly all patients have polyps in the upper gastrointestinal tract,
polyps in proximal stomach or fundus are small, multiple, and
hyperplastic with no risk of progression to cancer. 40 to 90 percent of
patients, however, may have adenomatous polyps in the distal stomach
antrum, duodenum, periampullary region, or even the terminal ileum .




             FAP of the colon
The relative risk of periampullary carcinoma is increased in patients with
familial adenomatous polyposis.


Surgical therapy is the only acceptable option for patients with familial
adenomatous polyposis after colonic polyps have been detected in the
form of colectomy and mucosal proctectomy followed by ileo-anal
anastomosis in 2 stages.


Medical therapy has gained increasing attention. Sulindac a NSAID,
has led to regression of polyps in limited animal studies, case reports,
and randomized, controlled trials .as it suppresses colonic epithelial –
cell proliferation.


The selective cyclooxygenase-2 (COX-2) inhibitor celecoxib has also
been shown to cause modest regression of colonic adenomas in patients
with FAP .
 Gardner's Syndrome

  Gardner's syndrome shares all the features of colonic plyposis
of familial adenomatous polyposis and also has an autosomal
dominant mode of inheritance.


Among the extracolonic manifestations of Gardner's syndrome
osteomas of the skull, mandible, and long bones, desmoid tumors;
dental abnormalities, lipomas, fibromas, neoplasms of the thyroid
and upper gastrointestinal polyps.


A particularly important, and potentially fatal complication is
desmoid tumour of the mesentry , occurs in 8 – 13 % of patients
as it may cause intestinal obstruction , ischemia & abscesses .
Mandibular osteoma in Gardeners syndrome
  Once familial adenomatous polyposis or Gardner's syndrome has
been identified, potentially affected persons should be screened
with flexible sigmoidoscopy at the age of 12 years. The procedure
should be repeated every two years if polyps are found, and
planning for surgery should be individualised.



Conversly, if no polyps are found, the procedure should be
performed every 3 years untill the patient reaches the age of
40, assuming that polyps do not develop.



Upper endoscopy should be performed every one to three
years to detect gastroduodenal polyps in patients with colonic
polyposis.
Peutz-Jeghers syndrome


 Peutz-Jeghers syndrome is an autosomal dominant disorder featuring
mucocutaneous pigmentation (eg, on the face, lips, and buccal mucosa)
and benign GI hamartomas.


These polyps may be found in the small bowel in up to 90% of
affected individuals. The stomach and colon are frequently involved,
and tumors outside the GI tract are also described.



Histologically, the lesions feature a distinctive frondlike appearance
with a stromal/smooth muscle core covered by acinar glands and
normal mucosa. Nuclear atypia is absent.
Secondary complications are common and are often related to the
significant numbers of hamartomas present within the bowel. Colicky
abdominal pain, GI bleeding, and obstruction (frequently the result of
intussusception) are widely described.



Malignant transformation is reported, and other nongastrointestinal
cancers may be found concomitantly.



Current surveillance recommendations for the small bowel lesions
include biannual barium upper GI series and flexible endoscopy
beginning at age 10 years.
Mucocutaneous pigmentations in peuz jegher syndrome
 Juvenile Polyposis


  Three forms of familial juvenile polyposis, all are autosomal dominant,
have been observed :familial juvenile polyposis coli ( in which polyps are
limited to the colon ), familial juvenile polyposis of the stomach, and
generalized juvenile polyposis ( in which polyps are distributed
throughout the gastrointestinal tract ).




The polyps are hamartomas covered by a normal glandular epithelium.
Either single or multiple, they are found mostly in the rectum in children
and sometimes adults. There is an increased risk of colon cancer among
those patients.
Colonic juvenile polyp
Cowden's Disease (Multiple Hamartoma Syndrome)

   A rare autosomal dominant disorder, characterised by multiple
hamartomatous tumors of ectodermal, mesodermal, and endodermal
origin. Mucocutaneous lesions are prominent, including facial lichenoid
and verrucous papules and oral papillomas. In addition to breast
lesions ranging from fibrocystic disease to cancer in 50 percent of
cases.

Gastrointestinal polyps are also reported and can be found anywhere in
the gastrointestinal tract , they are small and may be hamartomatous,
juvenile, lipomatous or inflammatory


Unlike the polyposis syndromes discussed , the gastrointestinal
polyposis in Cowden's Disease have no risk to turn malignant.
Neurofibromatosis


   Neurofibromatosis type I , or von Recklinghausen's disease, may
 include submucosal neurofibromas in the gastrointestinal tract.



There may be symptoms of abdominal pain or bleeding .




The malignant transformation of submucosal neurofibromas into
neurofibrosarcoma has been reported .
Benign small bowel tumors may develop as a single lesion or as
multiple lesions of several subtypes. The types of tumors include
the following :


   Hyperplastic polyps

  Hyperplastic polyps are benign mucosal growths frequently
  observed in the duodenum and proximal ileum.


  Frequently discovered upon routine upper endoscopy, the polyps
  may be single or multiple.


  They are generally asymptomatic with no malignant potential and may
  be removed endoscopically with biopsy forceps or an Endosnare
Hyperplastic polyp
  Adenomas
    Three types of small bowel adenomas have been described:
adenomatous polyps, Brunner gland adenomas, and villous adenomas.
In general, they may develop as single or multiple lesions, both sessile
and pedunculated .




       Sessile adenoma                     Pedunculated adenoma
Histologically, they appear as intraluminal extensions of the mucous
membrane and submucosal architecture with multiple acini supported
on a central fibrovascular core.



Complications of continued growth include obstruction, bleeding,
intussusception, and, occasionally, malignant degeneration, particularly
with larger villous lesions. Specifically, Brunner gland adenomas
develop most often along the posterior wall of the duodenum at the
junction of the first and second portions.




Villous adenomas, although exceedingly rare, have most frequently been
described in the duodenum. Bleeding and obstruction are their most
common complications; although, as with their counterparts in the colon
and stomach, they may be associated with malignant degeneration.
Gut stromal tumors
   In several reports, gut stromal tumors (formerly known as leiomyomas
and leiomyosarcomas) are the most common symptomatic small bowel
lesions. They have been found in all areas of the small bowel. Featuring
nests of spindle-shaped cells located between the muscularis propria and
muscularis mucosa, these intramural lesions may form intraluminal
masses, extraluminal masses, or transmural (dumbbell-shaped) lesions.




      Colonic leiomyoma
Histological features of smooth muscle may or may not be seen with light
microscopy; however, this finding has not yet been assigned any
prognostic value. Both focal and annular lesions have been described,
often with features of surface ulceration and/or deeper necrosis. Such
degeneration may lead to bleeding and marked hemorrhage, which are the
most common complications observed with this family of tumors.




Other complications of gut stromal tumors include bowel obstruction,
intussusception, tumor perforation, and potential malignant degeneration..



Differentiating between benign and malignant gut stromal tumors can be
difficult. In several recently published reviews, benign smooth muscle tumors
are generally 2-3 times more common than the sarcoma variants.
Intraoperative view of an ependymal
     small bowel stromal tumor.
Ependymal small bowel stromal
    tumor after removal.
  Lipomas

Small bowel lipomas are benign submucosal tumors of mesenchymal
origin.


They may be sessile or ependymal and may grow undetected to a size
sufficient to produce symptoms of colicky abdominal pain and
intermittent bowel obstruction. Intussusception has also been reported.


Histological features include collections of mature adipose tissue
and fibrous tissue strands. Evidence of surface ulceration, central
necrosis, and hemorrhage may be present. Collections of adipose
tissue may be found near the ileocecal valve. These deposits may
clinically mimic other lesions, both radiographically and
endoscopically.
Colonic lipoma
 Hemangiomas


Hemangiomas of the small bowel are rare vascular tumors of 3 types:
capillary, cavernous, and mixed. Cavernous hemangiomas are most
common .



Hemangiomas may be solitary or multiple and may account for up to
10% of small bowel lesions.



With light microscopy, they appear as blood-filled sinusoidal spaces
intermingled with varying amounts of connective tissue.
Occasionally, the lesions contain smooth muscle cells.
GI bleeding is a frequent complication. The blood loss may be chronic
(resulting in long-standing occult anemia) or profound (requiring massive
transfusions and/or emergent laparotomy for control of acute
hemorrhage).



Additional uncommon complications include small bowel obstruction,
intussusception, intramural hematoma, and perforation.



Diagnosis and localization of symptomatic lesions remains a
challenge. Preoperative arteriography or intraoperative maneuvers,
such as transillumination of the bowel or intraoperative ultrasound,
may be employed to increase localization success.
              Lymphomatous polyposis
There is two types include :
     Multiple lymphomatous polyposis.
     Mediterranean type lymphoma.




Lymphoid hyperplasia            Ileal lymphoid polyps
Inflammatory polyps ( pseudopolyps )

May be seen in inflammatory bowel disease, but are less frequent in crohn’s
disease than in ulcerative colitis
Thank you
Lab Studies:

Results from routine laboratory testing do not reveal abnormalities in most
patients with small bowel tumors or polyps .


Fecal occult blood test: Large adenomas can bleed intermittently
Quantitative testing of stool for blood has been tried , Newer
immunologically based tests designed to detect only human blood in
stool are becoming available and are expected to increase the
specificity of the test.



Stool testing for genetic alterations that occur in adenomas is being
studied. Thus far, the stool tests are more sensitive for cancers and
advanced adenomas than for small tubular adenomas
Microcytic anemia may be observed in conjunction with vascular or
ulcerated bleeding lesions .




 Low serum iron and ferritin and an increased total iron-binding
 capacity (TIBC) can be observed because of blood loss in some
 patients with colonic adenomas and carcinomas




Electrolyte abnormalities are not commonly identified in patients with
small bowel tumors.
Imaging Studies:

Findings from plain films of the abdomen are frequently normal


Larger lesions may demonstrate signs of complete or partial small bowel
obstruction (eg, dilated small bowel, air-fluid levels, volvulus).

Barium contrast studies (upper GI series, small bowel enteroclysis) are
the most frequently used diagnostic tools.

Images from upper GI series may demonstrate the lesion in up to
29% of cases .


The radiographic appearance on upper GI series includes irregular
mucosal surfaces, extraluminal, barium-filled cavities (showing central
lesion necrosis), and dumbbell-shaped lesions (indicating intraluminal
and extraluminal growth).
In recent reports, CT scan images of the abdomen demonstrate up to 27%
of benign small bowel tumors .

Gut stromal tumors larger than 2 cm are frequently imaged successfully
using a CT scan. Accurate size, evidence of ulceration, and lesion
necrosis are often detected .


Ultrasound images of the abdomen may demonstrate larger tumors
(>4 cm) and can help differentiate intraluminal, intramural, and
extraluminal growth patterns .



 Barium enema helps identify distal ileal lesions with successful reflux of
 contrast through the ileocecal valve.
 Upper G.I. endoscopy


Upper endoscopy has been employed successfully for the detection of
proximal benign small bowel lesions in 12-30% of recently reported
cases.

Endoscopy allows concomitant biopsy of intraluminal lesions.
Polypectomy may also be performed for small lesions.



Gut stromal tumors and lipomas frequently cannot be removed via
endoscopy because of their deep intramural location and the subsequent
elevated risk of bowel perforation during attempted removal. In addition,
some authorities caution against endoscopic lesion biopsy because of
increased risk of shedding cells, which could lead to nests of local tumor
recurrence.
Capsule endoscopy


   The newer modality of capsule endoscopy has been successfully used
to detect small bowel lesions that have previously remained undiagnosed
by other methods

Both color video images and transit time values can be analyzed for
regional mucosal abnormalities.


Solid benign tumors, such as leiomyomas, as well as vascular lesions
(eg, angiodysplasia, varices), have been identifed in patients through
the use of capsule endoscopy
 Arteriography

   Selective arteriography may be used for diagnosis of possible
vascular lesions and potential embolization of active bleeding.


Both subserosal tumors and hemangiomas may be identified by
characteristic tumor blush visualized on arteriograms. Additional clues
include multiple feeding arteries, irregular draining veins, and venous
pooling around the lesion.


Arteriography may assist in differentiating malignant from benign
lesions. Benign tumors frequently receive arterial supply from either the
gastroduodenal or superior mesenteric arteries. Malignant lesions often
demonstrate aberrant arterial inflow from renal arteries, lumbar arteries,
or both.
  Arteriogram demonstrating
 small bowel gut stromal tumor,
indicated by round tumor blush
   in lower right corner of the
              image.
Surgical Care:

Surgical excision of small bowel tumors remains the recommended
therapy. Exploratory laparotomy with excision of the lesion provides
the safest and most direct method for lesion identification and
treatment.

Tumors discovered incidentally at laparotomy should be removed to
prevent future symptom development and secondary complications.


Both segmental resection and enterotomy/polypectomy have been
used for lesion removal. If the pathology cannot be established at
the time of resection, full segmental resection with adequate margins
is recommended

Current literature confirms an excellent prognosis for tumors resected
prior to tumor perforation or onset of massive GI hemorrhage.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:38
posted:8/19/2012
language:English
pages:39