Diverticular Disease. Colonic Tumors · •Diverticulosis refers to the presence of diverticula in an individual who is asymptomatic, whereas diverticular disease refers to the presence

Diverticular Disease. Colonic Tumors

Diverticular Disease.

• DIVERTICULOSIS

• ESSENTIALS OF DIAGNOSIS

• Radiographic or endoscopic demonstration of diverticula.

• Normal vital signs and laboratory evaluation.

• Absence of complications (diverticulitis, diverticular hemorrhage).

Diverticulosis

• Diverticula are acquired herniations of the colonic mucosa and submucosa through the muscularis propria.

• They occur most commonly in the sigmoid colon and can vary in size and number, although typically they are between 5 and 10mm in diameter.

• Diverticulosis refers to the presence of diverticula in an individual who is asymptomatic, whereas diverticular disease refers to the presence of diverticula associatedwith symptoms, which occurs in 20% of individuals with diverticula.

• It is estimated that diverticulosis affects less than 5% of people at the age 40, 30% of people by age 60, and 50–65% of people by age 80.

• An exception to this is in vegetarians, in whom the prevalence of diverticula is much lower, presumably due to diets that are higher in fiber.

• Men and women are affected equally.

• The prevalence and distribution of diverticula vary throughout the world. Whereas diverticula are common and predominantly left-sided in Western countries (95% involve the sigmoid colon), in urbanized areas of Asia, such as Japan, Hong Kong, and Singapore, the prevalence is only 20% and the diverticula are predominantly right-sided, even among those who have adopted a Western-style, low-fiber diet.

• Pathogenesis

• A. Colonic Motility

• Segmentation within the colon is thought to play an importantrole in the development of diverticula.

• Segmentation refers to the process by which a short segment of the circular muscle of the colon contracts in a nonpropulsive manner.

• These elevated intraluminal pressures may ultimately result in herniation of the mucosa and submucosa at sites of weakness (namely, where the vasa recta penetrate the muscularis propria between the taeniae coli), resulting in the formation of diverticula.

• B. Colonic Wall Changes

• The colonic wall may be weakened by the breakdown and damage of mature collagen, as well as by the synthesis of immature collagen.

• The importance of structural changes in the colonic wall is suggested by the early formation of diverticulain patients with connective tissue disorders, such as Marfan syndrome, Ehlers-Danlos syndrome, and polycystic kidney disease.

• C. Inflammation

• Patients with diverticulosis may exhibit low-grade colonic inflammation that may resemble inflammatory bowel disease histologically.

• Histologic findings include nonspecific mucosal inflammation, crypt abscesses, a mononuclear cellinfiltrate in the lamina propria, and occasional submucosal inflammation or granulomas.

• Possible causes include ischemia, changes in bacterial flora, mucosal prolapse, and the presence of intraluminal antigens.

• D. Fiber

• The role of fiber in the development of diverticulosis was first suggested by epidemiologic evidence.

• Diverticula rarely develop in rural Asia or Africa (prevalence of <0.2%), where diets are high in fiber.

• However, in areas that have developed economically and have adopted Western dietary habits, diverticula become more prevalent.

• In addition, populations that have moved from rural to urban environments show an increased prevalence of diverticulosis.

• Clinical Findings

• A. Symptoms and Signs

• The majority of patients with diverticulosis are asymptomatic,with only 20% developing symptoms over their life span.

• Abdominal pain is the most common symptom, and is usually localized in the left lower quadrant.

• In patients with right-sided diverticula, the pain can be felt in the right lower quadrant.

• The pain may worsen after eating and in some is relieved with the passage of stool or flatus.

• Patients may also complain of nausea, cramping, irregular bowel movements (intermittent diarrhea or constipation),bloating, and flatulence.

• Patients do not demonstrate abnormal vital signs, such as tachycardia or fever in uncomplicated diverticulosis.

• With palpation of the left lower quadrant, mild tenderness and voluntary guarding may be present.

• B. Laboratory Findings

• In uncomplicated diverticulosis, laboratory values, including the hematocrit, hemoglobin, and white blood cell count, are normal and Hemoccult testing of the stool is negative.

• C. Imaging Studies

• A double-contrast barium enema will demonstrate the presence, localization and number of diverticula.

• Diverticulosis can also be seen on abdominal computed tomography (CT) with oral or rectal contrast.

• D. Endoscopy

• Diverticulosis is frequently discovered during colonoscopy as an incidental finding

• Colonoscopy, however, can be difficult to perform in patients with diverticulosis due to narrowing of the colonic lumen and possible colonic fixation from prior episodes of diverticulitis resulting in inflammation and pericolic fibrosis.

• Colonoscopy is relatively contraindicated in patients in whom acute diverticulitis is suspected, due to an increased risk of colonic perforation.

• Differential Diagnosis

• Many of the signs and symptoms of symptomatic diverticulosis are also seen in irritable bowel syndrome.

• Irritable bowel syndrome frequently causes diffuse abdominal pain; thus, pain localized to the left lower quadrant in the setting of demonstrated diverticula supports a diagnosis of uncomplicated diverticulosis.

• Mild diverticulitis can also manifest similarly and is not ruled out by the absence of a fever, elevated white blood cell count, or other signs of infection.

• Other pelvic infections, such as appendicitis and pelvic inflammatory disease, can also mimic diverticulosis.

• Other causes of lower abdominal pain that need to be considered are infectious colitis, inflammatory bowel disease, ischemic colitis, colorectal cancer, and endometriosis.

• Complications

• Diverticulosis can be complicated by acute diverticulitis, which results from the perforation of a diverticulum, as well as by hemorrhage, which occurs when the arteriole associated with the diverticulum erodes.

• Treatment

• Most patients with diverticulosis do not require any specific treatment, and there are no medical treatments that will lead to the regression of diverticula, once present.

• Therapies used to treat uncomplicated diverticular disease include fiber-rich diets,nonabsorbable antibiotics, mesalazine, probiotics, and prebiotics.

• Prognosis

• Twenty percent of patients with diverticula will develop symptoms of uncomplicated diverticular disease, while 10–25% of patients with diverticulosis will go on to develop a complication

• Fortunately, most episodes of diverticulitis and diverticular hemorrhage are self-limited and can be managed medically.

• ACUTE DIVERTICULITIS


• Abdominal pain and tenderness (typically left lower quadrant).

• Fever, or leukocytosis, or both.

• Characteristic radiographic findings.

• General Considerations

• diverticulitis results from the micro or

• macroperforation of a diverticulum, resulting in anything from subclinical inflammation to feculent peritonitis.

• It affects 10–25% of patients with diverticulosis

• Acute diverticulitis can be either complicated or uncomplicated.

• The severity of diverticulitis is often described usingthe Hinchey classification

• Hinchey et al 3 proposed a classification for acute diverticulitis, that has been variously adapted, and is useful not only in academia but also in outlining successive stages of severity

• stage 1a - phlegmon

• stage 1b - diverticulitis with pericolic or mesenteric abscess

• stage 2 - diverticulitis with walled off pelvic abscess

• stage 3 - diverticulitis with generalised purulent peritonitis

• stage 4 - diverticulitis with generalised faecal peritonitis

http://radiopaedia.org/articles/diverticulitis

• Pathogenesis

A. Elevated Colonic Pressure

• Most cases of diverticulitis are the result of erosion of the diverticular wall due toincreased intraluminal pressure or inspissatedfood particles.

• This then leads to inflammation and focal necrosis, with resultant perforation of the thin-walled diverticulum.

B. Changes in Bacterial Flora

• Altered microbial composition within the gut, possibly due to effects on the innate immune system that allow normal commensal flora to act pathologically, may impair the mucosal barrier, resulting in chronic low-grade inflammation.

• Secretion of mucus and bacterial overgrowth can occur when food particles become inspissated within a diverticulum.

C. Nonsteroidal Anti-Inflammatory Medications

• Nonsteroidal anti-inflammatory medications (NSAIDs) have been associated with diverticulitis and perforation.

• The association of NSAIDs with diverticulitis is postulated to be related to decreased prostaglandin synthesis and direct topical mucosal damage.

• In addition, NSAIDs are weak acids that may denude epithelial cells, resulting in increased mucosal permeability, ulceration, and the translocation ofbacteria and toxins.

D. Diet

• A diet low in fiber may not only predispose to the formation of diverticula, it may also predispose to the development of diverticulitis.

• Red meat intake has also been associated with diverticulitis.

E. Smoking, Alcohol, Coffee, and Caffeine

• No association between complicated diverticular disease and smoking.

• Alcohol, coffee, and caffeine have not been shown to increase the risk for diverticulitis.



• Diverticulitis should be suspected in a patient presenting with lower abdominal pain, fever, and leukocytosis.

• In the West, left lower quadrant pain is the most common complaint (70%).

• The onset is usually gradual, and the pain may

be present for several days prior to the patient’s seeking medical attention.

• The pain is constant, with intermittent exacerbations that are associated with colonic spasms and are followed by loose bowel movements.

• Patients may also complain of nausea and vomiting (20–62%), constipation (50%),diarrhea (25–35%), and urinary symptoms (10–15%).

• The pain is typically localized in patients with Hinchey stage I and II disease, as the inflammation is confined to the pericolic tissue.

• An area of localized tenderness with swelling and erythema of the abdominal wall suggests an underlying abscess progressing to form a colocutaneous fistula.

• Patients with stage III and IV disease have symptoms of generalized peritonitis, including severe, diffuse abdominal pain.

• In stage IV disease, because free perforation has occurred, the onset of the pain is often acute and severe.

• On examination, tenderness is usually present in the leftlower quadrant, with a tender mass being present in 20%.

• A lowgrade or high-grade fever is common.

• Diffuse tenderness suggests free perforation and peritonitis.

• In cases of free perforation, hemodynamic instability may develop, along with a rigid abdomen.


• The most common finding is a leukocytosis

• The serum amylase is either normal or mildly elevated.

• Severe episodes may also be associated with hyponatremia, impaired renal function, and acidosis as a result of sepsis.

• If the urinary bladder is involved, pyuria or hematuria may result, and polymicrobial urinary tract infections can be seen with a colovesical fistula.


• Plain abdominal radiographs are typically normal in patients with mild diverticulitis, but in the setting of severe disease, there may be an ileus pattern, or, if obstruction is present, proximal bowel dilation.

• A large abscess may be associated with an air-fluid level on upright films.

• If there is perforation into the retroperitoneal space, the psoas shadow may be obliterated

• Free air under the diaphragm may be seen on upright films in the setting of intraperitoneal perforation

• Ultrasound may identify a phlegmon, abscess, or bowel wall thickening.

• CT scanning is currently the radiographic test of choice for diagnosing diverticulitis.

• The following findings are seen with diverticulitis: soft tissue density ofthe pericolic fat (98%), diverticula (84%), bowel wall thickening of more than 4 mm (70%), and phlegmon or pericolic fluid (35%).

• D. Endoscopy

• During an acute episode of suspected diverticulitis, rigidproctoscopy, flexible sigmoidoscopy, and colonoscopy arerelatively contraindicated.

• Patients who have not previously had a colonoscopy should have one to exclude an underlying malignancy or other disorder, with a waiting period of 6–8 weeks followingresolution of the episode of diverticulitis.

• Findings of diverticulitis on endoscopy include edema, erythema, strictures, and (rarely) purulent drainage from a diverticulum.

• Following resolution of an episode of diverticulitis, endoscopicfindings are often minimal.


• The differential diagnosis includes :

• inflammatory bowel disease,

• ischemic colitis,

• infectious colitis,

• appendicitis,

• cancer,

• Complicated peptic ulcer disease,

• pyelonephritis,

• pelvic inflammatory disease,

• ovarian cyst or torsion,

• and ectopic pregnancy.

• Complications

• are seen in 15–20% of patients

• include pericolic or pelvic abscess formation,perforation with purulent or feculent peritonitis, fistula formation to adjacent organs, colon obstruction, and sepsis.

• Peritonitis is associated with a significant mortality rate.

• Mortality is approximately 6% if there is purulent peritonitis and 35% if there is feculent peritonitis.

• Treatment

• A. Medical Therapy

• Hospitalization and intravenous administration of antibiotics is usually recommended for the elderly,immunosuppressed, those with significant comorbid illnesses, and those with a high fever or significant leukocytosis.

• Therapy consists of bowel rest and antibiotics.

• Outpatients should be put on a clear liquid diet,with slow advancement of the diet once clinical improvement is seen.

• Outpatient regimens

• Metronidazole plus 500 mg three times daily Oral

• Ciprofloxacin 500 mg twice daily Oral

• Amoxicillin–clavulanate 875/125 mg twice daily Oral

• Inpatient regimens

• Metronidazole plus 500 mg every 8 hours IV

• ciprofloxacin or 400 mg every 12 hours IV

• levofloxacin or 500 mg daily IV

• ceftriaxone or 1–2 g daily IV

• Cefotaxime 1–2 g every 6 hours IV

• Ampicillin–sulbactam 3 g every 6 hours IV

• Piperacillin–tazobactam 3.75 or 4.5 g every 6 hours IV

• Ticarcillin–clavulanate 3.1 g every 8 hours IV

• Imipenem 500 mg every 6 hours IV

• Meropenem 1 g every 8 hours IV

• B. Radiologically Guided Therapy

• Some patients can be managed with percutaneously placed catheters.

• Drains are usually placed through the anterior abdominal wall, although transgluteal,transrectal, or transvaginal approaches arealso used for abscesses deep within the pelvis.

• Patients who fail to improve with catheterdrainage require surgery.

• C. Surgical Therapy

• Indications for surgery during an episode of diverticulitis include diffuse peritonitis, obstruction, and failure of medical therapy.

• Fifteen to 30% of patients will require surgery

• Patients requiring emergency surgery usually undergo a two-stage procedure.

• Prognosis

• Patients requiring surgery for free perforation have a mortality rate of 30% compared with 1% for those undergoing elective surgery.

• Up to 30% of patients will go on to develop recurrent diverticulitis.

• For patients who have undergone a surgical resection, 1.0–10.4% will develop recurrent diverticulitis, with 0–3.1%requiring an additional resection.

• Twenty-seven to 33% will complain of persisting symptoms.

• DIVERTICULAR HEMORRHAGE


• Hematochezia, maroon stool, or melena.

• Nasogastric lavage that is negative for blood.

• Endoscopic or radiographic demonstration of diverticula.

• Exclusion of other bleeding sources.


• Up to 15% of patients with diverticulosis will develop diverticular bleeding, bleeding that will be massive in approximately one third of the patients.

• Mortality rates for massive hemorrhage are significant, at 10–20%, in large part because many patients with diverticular hemorrhage are elderly with comorbid illnesses.

• Pathogenesis

• Diverticula form at the site of penetration of the vasa recta through the muscularis propria.

• In 50–90% of patients, the source of bleeding is right-sided diverticula (despite the fact that 75% of diverticula are located on the left).

• Rightsided diverticula have wider necks and domes, so a longer portion of the vasa recta is exposed to injury.



• Patients typically present with moderate to large amounts of maroon stool or hematochezia.

• Melena may occasionally be seen in cases of right-sided bleeding.

• The bleeding is typically painless.

• On examination, pallor, tachycardia, orthostatic hypotension, or shock may be noted with massive hemorrhage.

• Rectal examination shows gross blood, which can range from bright red to melenic.

• Nasogastric lavage should be considered to evaluate for a possible upper gastrointestinal source of bleeding.


• Red cell indices should indicate anormochromic, normocytic anemia.

• The presence of a hypochromic, microcytic anemia suggests chronic blood loss from another source.


• Radionuclide scanning using technetium sulfur colloid or 99mTc pertechnetate–labeled red blood cells can be used to identify acute bleeding and to localize the site of bleeding.

• The major limitation of radionuclide scanning is that localization is imprecise and can only identify an area of the abdomen where the bleeding is occurring, and not an exact site.

• An alternative to nuclear imaging is dynamic enhanced helical CT scan.

• Angiography has the advantage of being both diagnostic and therapeutic.

• Angiography is successful in identifying a source of bleeding in 14–85% of cases.

• Plain abdominal films are not helpful in identifying a source of lower gastrointestinal hemorrhage, and barium enemas are contraindicated because the presence of barium interferes with the performance of angiography and colonoscopy.

Radionuclide scanning

• D. Endoscopy

• Urgent colonoscopy will lead to a definite or presumptive diagnosis in 74–90% of patients.

• Although visualizing active bleeding is uncommon, a presumptive source can be identified through the visualization of an adherent clot or a mucosal lesion.


• Diverticular bleeding is the most common cause of maroon stool or hematochezia, and accounts for 42–56% of acute lower gastrointestinal bleeding.

• Angiodysplasias are responsible for 20–30% of cases of hematochezia.

• Colon cancer is the most common cause of lower gastrointestinal blood loss, but accounts for less than 10% of lower gastrointestinal hemorrhage.

• Massive upper gastrointestinal hemorrhage or small bowel hemorrhagecan also manifest with hematochezia.

• Rectal causes of lower gastrointestinal hemorrhage include ulcers, radiation proctopathy, varices, and Dieulafoy lesions.

• Massive hemorrhoidal bleeding is rare.

• Rarely, inflammatory bowel disease can result in massive lower gastrointestinal hemorrhage.

• Complications

• Complications of diverticular hemorrhage are the result of massive blood loss, including death from exsanguination.

• Ischemic injuries to the heart, brain, or kidneys are the most common manifestations, especially in the elderly.

• Treatment

• A. Medical Therapy

• In 75–90% of patients, bleeding stops spontaneously.

• Initial therapy focuses on resuscitation.

• If a bleeding source is identified endoscopically, therapy with injection of epinephrine (1:10,000 to 1:20,000) followed by thermal coagulation is recommended; if a nonbleeding visible vessel is seen, electrocautery alone can be applied.

• An alternative to electrocautery is the placement of hemoclips.

• If a bleeding source is identified with angiography, therapy can be carried out. Vasopressin infusion will stop bleeding in up to 91% of patients, but 50% will rebleed when the vasopressin is stopped.

• Transcatheter embolization using polyvinyl alcohol particles or microcoils is a potentially more definitive method for controlling hemorrhage.

• B. Surgical Therapy

• Persistent hemodynamic instability will necessitate surgery in 18–25% of patients who have required blood transfusions.

• Once the source of bleeding has been localized (either preoperatively or intraoperatively), segmental colectomy is performed.

• If a bleeding source cannot be identified, a subtotal colectomy should be performed.

• Prognosis

• Seventy-five to 90% of patients will stop bleeding spontaneously.

• The risk of recurrent bleeding is 10–40% (oftenwithin 48 hours of the initial bleed), and after a second episode, the risk of recurrent hemorrhage increases to 21–50%.

• The overall mortality rate for those with massivehemorrhage is 10–20%.

• The overall operative mortality rate is approximately 10%.

Colorectal Cancer


• CRC is the second leading cause of cancer death in the United States and Western Europe.

• The lifetime risk of CRC is approximately 6%.

• 1 in 18 men and women will be diagnosed with CRC during their lifetime.

• It is estimated that the adenoma to carcinoma sequence unfolds over a 7- to 10-year period.

• Pathogenesis

• In 1990, a stepwise, chronologic model for colorectal tumorigenesis was proposed.

• It outlined sequential alterations in key growth regulatory genes, such as APC, K-ras, and tp53, culminating in the development of a malignant neoplasm.

• This pathway contributes to the development of 85% of colorectal tumors that arise from preexisting adenomatouspolyps.

Hereditary GastrointestinalCancer Syndromes


• Approximately 3–5% of colorectal cancers are caused by inherited gene mutations associated with hereditary nonpolyposis colorectal cancer (Lynch syndrome) or familial adenomatous polyposis.

• Genetic testing is clinically available for several hereditary gastrointestinal cancer syndromes and can be used to guide cancer screening recommendations.


• The majority of cases of gastrointestinal cancer are believed to be sporadic events; however, inherited factors play a role in development of some tumors, with an estimated 5% being attributable to a single gene mutation.

• Hereditary gastrointestinal cancer syndromes convey a markedly increased risk for developing cancer and require specific strategies for diagnosis and management.

• 1. Lynch Syndrome (Hereditary Nonpolyposis Colorectal Cancer)

• HNPCC is the most common hereditary CRC syndrome and is estimated to account for 3-5% of CRC cases.

• Lynch syndrome should be suspected in families that have multiple relatives affected with CRC or related extracolonic tumors, or both, and in individuals whoare diagnosed with CRC at a young age, have synchronous or metachronous colorectal cancers, or develop multiple HNPCC-associated tumors.


• CRC is usually the predominant cancer in most families with Lynch syndrome.

• Endometrial (uterine) cancer is the second most common cancer described in Lynch syndrome families, and women have a 40–60% lifetime risk for developing this malignancy.

• The lifetime risks for developing other Lynch-associated cancers, such as urinary tract cancers, ovarian cancer, and other gastrointestinal cancers (stomach, pancreas, small intestine), are also increased for individuals with Lynch syndrome and are estimated to be between 10–20%.

• Brain tumors (eg, glioblastomas and astrocytomas) have been described in the Turcot syndrome variant of Lynch syndrome.

• Cutaneous sebaceous adenomas and sebaceous carcinomas are rare skin tumors seen in the Muir-Torre variant.

• B. Genetic Features

• The increased predisposition to developing cancer in Lynchsyndrome is the result of autosomal dominantly inheritedmutations in genes involved in DNA mismatch repair (MMR).

• Mutations in the genes hMLH1 and hMSH2 account for more than 80% of the identified MMR alterations in Lynch syndrome families.

• Mutations in the MMR gene hMSH6 have been identified in approximately 10% of Lynch syndrome families.

• Mutations in hPMS2 in rare families.

• Management

• The high lifetime risk of colorectal and other extracolonic cancers, the accelerated progression of adenomas toadenocarcinomas, and the young age of onset of colorectal neoplasia require specialized strategies for cancer prevention.

• A. Colorectal Cancer Screening

• Individuals who are at risk for Lynch syndrome should begin having colonoscopies at age 20–25 years, with repeat examinations every 1–2 years.

• The endoscopist should be vigilant for small or flat lesions, which may be associated with higher malignant potential in Lynch syndrome patients than in the general population.

• B. Endometrial Cancer Screening

• Women at risk for Lynch syndrome undergo endometrial cancer screening with annualtransvaginal ultrasound and endometrial biopsy beginning at ages 25–35 years.

• Women who have completed childbearing should be counseled to consider prophylactic hysterectomy.

• C. Screening for Other Cancers

• For urinary tract cancer screening it is recommended annual urine cytology.

• Screening for ovarian cancer includes transvaginal ultrasound and checking serum CA-125 levels once yearly.

• Individuals with Lynch syndrome from families with Muir-Torre should have annual dermatologic examinations to screen for cutaneous sebaceous neoplasms.

• Screening for gastric cancer and small intestinal cancer using upper endoscopy has been proposed by some experts.

• At present there are no recommendations for screening for pancreatic or central nervous system tumors because of lack of evidence to support effectiveness.

• D. Prophylactic Surgery

• Prophylactic colectomy

• Prophylactic hysterectomy and oophorectomy may be the most effective way to reduce risks of gynecologic cancer.

• E. Clinical Genetic Testing

• The most efficient strategy for genetic testing is to begin genetic evaluation with an individual who has a cancer diagnosis.

• Starting with evaluation of a CRC tumor specimen for features of microsatellite instability and loss of immunohistochemical staining for MLH1, MSH2, MSH6, and PMS2 proteins.

• Clinical genetic testing for germline mutations in theMLH1, MSH2, and MSH6 genes can be performed on DNA extracted from a peripheral blood sample.

• 2. Familial Adenomatous Polyposis

• Familial adenomatous polyposis (FAP) is the second most common inherited CRC syndrome.

• The classic FAP phenotype is one of hundreds to thousands of adenomatous polyps in the colon, with a nearly 100% risk of developing CRC.

• FAP accounts for approximately 1% of CRC cases.

• The incidence of FAP is approximately 1 in 10,000 persons.

• Although most cases arise in families with a known history through autosomal-dominant inheritance, approximately 30% of cases emerge as de-novo gene mutations in the APC gene.

• Clinical Finding• Most individuals with classic familial polyposis develop numerous

colorectal adenomas by the second or third decade of life.• More than half of individuals affected with colonic polyposis develop

adenomatous polyps in the upper gastrointestinal tract.• Extracolonic malignancies associated with FAP include papillary thyroid

cancer, adrenal carcinomas, and central nervous system tumors (Turcot syndrome).

• Children have an increased risk of developing hepatoblastomas.• Intra-abdominal desmoid tumors can appear in some individuals with FAP.• Desmoid tumors define the Gardner syndrome variant of FAP.• Other physical findings associated with FAP include the presence of extra

teeth, osteomas of the jaw and skull, and epidermoid cysts.• Congenital hypertrophy of the retinal pigment epithelium is an

ophthalmologic finding that should prompt evaluation for FAP.

Congenital hypertrophy of the retinal pigment epithelium

FAP

FAP

Osteomas of the skull

• B. Genetic Features

• Most cases of FAP are caused by germline mutations in the adenomatous polyposis coli (APC) gene.

• Mutations in the APC gene are detected in more than 80% of patients with the classic FAP phenotype of hundreds to thousands of adenomas.

• Management• Patients at risk of developing FAP should begin annual

colorectal screening for polyps with flexible sigmoidoscopy or colonoscopy by age 11.

• Total proctocolectomy with ileoanal anastomosis is the preferred operation.

• Once patients are found to have colorectal adenomas, upper endoscopy is recommended to assess for adenomas in the duodenum and ampulla.

• Patients with FAP are at increased risk for papillary thyroid cancer, annual thyroid examinations or thyroid ultrasound scans are recommended.

• Family members of individuals with FAP should be offered genetic testing for the gene mutation

• 3. Multiple Adenomas or Attenuated• Adenomatous Polyposis• Individuals with 10–100 colorectal adenomas are considered to have a

phenotype of multiple or attenuated polyposis.• Current practice guidelines recommend genetic evaluation for patients

with more than 20 colorectal adenomas.• Cancer prevention in patients with attenuated polyposis focuses on

frequent endoscopic surveillance with polypectomies to clear the colonic mucosa of adenomas; if adenomas are too numerous or recur too quickly to be managed endoscopically, then surgical colectomy may be indicated.

• Family members of affected individuals should begin colonoscopic screening 5–10 years younger than the age at which polyps appeared in the proband.

Documents

Diverticular Disease. Colonic Tumors · •Diverticulosis refers to the presence of diverticula in an individual who is asymptomatic, whereas diverticular disease refers to the presence