transformation of the periampullary adenoma to adenocarcinoma.1

Crohn Disease

Crohn disease is a significant risk factor to develop small bowel adenocarcinoma. The duration of

disease, distal jejunal or ileal disease, early age of diagnosis, fistulizing-type disease, and male gender

all contribute to a higher risk for development of small bowel adenocarcinoma.7 The relative risk was

reported as 33 (95% CI: 15.9 to 60.9).8 The areas particularly susceptible are where longstanding

inflammation has caused stricture formation. In these areas, the tumor tends to occur after at least 10

years of inflammation, and commonly contains signet-ring cell features similar to those found in colon

cancer due to ulcerative colitis.

Celiac Disease

There is an increased risk for small bowel lymphomas as well as small bowel adenocarcinoma with

those patients affected by celiac disease. Lymphomas tend to be both T-cell and non-Hodgkin

lymphomas.9

Peutz–Jeghers Syndrome

This is an autosomal dominant syndrome characterized by hamartomatous polyps in the gastrointestinal

tract and mucocutaneous melanin pigmentation. The increased risk of cancer is for breast, ovarian,

testicular, pancreas, stomach, esophagus, and others. The mutation has been identified on the

serine/threonine kinase 11 (STK 11) gene. Meta-analysis of Peutz–Jeghers syndrome indicated a relative

risk for small bowel cancer of 520 when compared to the general population.10

Hereditary Nonpolyposis Colorectal Cancer

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant gene that is associated

with the mutation of mismatch repair genes. There is an increased risk to develop small bowel cancer

with a relative risk of greater than 100 in carriers for the gene mutation.11

Other Familial Syndromes

Multiple endocrine neoplasia type 1 (MEN-1), von Hippal–Lindau syndrome, and neurofibromatosis type

1 all carry increased risk for developing neuroendocrine, or carcinoid tumors.9

Dietary and Lifestyle Predisposition

There are several indicators to the increased risk of developing small bowel cancer including cigarette

smoking, increased BMI/obesity, red meat consumption, and alcohol consumption.9

CLINICAL PRESENTATION

4 The majority of these tumors, whether benign or malignant, are typically asymptomatic and are

encountered incidentally. The biggest factor relating to the way small bowel tumors present is the size

and location within the small bowel. Generally, tumors less than 4 cm are asymptomatic. This is even

truer with benign lesions. The most common presenting symptoms are weight loss (30% to 50%),

nausea, vomiting, anemia, and abdominal pain.9 Late detection of asymptomatic malignant tumors

results in metastases in about 50% of patients at the time of diagnosis.12 Ulceration, perforation (in

cases of lymphoma), obstruction, or bleeding are the most common presenting symptoms.13

Intussusception or volvulus can occur rarely. NETs can present as functional syndromes, such as

“carcinoid syndrome” with flushing, diarrhea, and tachycardia with late valvular dysfunction due to

fibrotic scarring induced by serotonin (Table 51-1).

DIAGNOSIS

Examining the small bowel with accuracy is a difficult process. Upper and lower gastrointestinal

endoscopy provides little information because of the limited access to the vast amount of mucosal

surface. Colonoscopic intubation of the ileocecal valve is ideal but is not possible in about 5% to 10% of

the patients.14 Even with this intubation, only the most distal 25 cm of the terminal ileum can be

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surveyed. During upper endoscopy (EGD) the duodenum is visualized in the proximal portion typically

leaving the distal duodenum and the rest of the small bowel unevaluated. In certain cases, and with

maximal effort, the endoscope can be advanced beyond the ligament of Treitz. However, the risk of

duodenal injury increases due to pressure in the curve of the duodenum. Nevertheless, both of these

procedures are indicated to begin the workup. The entire small bowel needs to be evaluated for a source

of the symptoms. Newer modalities have been developed to facilitate evaluation of the small bowel.

Table 51-1 Complications Resulting From Small Bowel Tumors

CAPSULE ENDOSCOPY

CE is an ingestible miniature camera that is capable of producing images throughout the small bowel to

depict its entire mucosal lining. CE was introduced first in 2000. CE is used most commonly to evaluate

the small bowel for a source of occult gastrointestinal bleed (OGIB).

Generally, CE is safe and widely used as a diagnostic test.15 The only contraindications to its use are

patients having swallowing disorders or bowel obstruction, with the possibility of capsule retention.

There is a 2% capsule retention rate in most series.16 Other limitations to CE are that it is time

consuming; there is no biopsy potential, and no therapeutic capability.

A large meta-analysis completed by Triester et al.17 demonstrated the incremental yield of CE over

enteroscopy and small bowel barium radiography to be 35% and 59%, respectively. Although not

statistically significant, the rate of identifying lesions was higher with CE. This is not surprising given

CE’s ability to evaluate more mucosal surface area than other modalities. Lewis et al. performed a metaanalysis of CE compared to small bowel barium swallow, EGD, colonoscopy, and small bowel

enteroscopy. Detection rate for CE was 87% and missed lesion rate was 10%. The combination of the

other 4 modalities yielded a 13% detection rate and missed lesion rate of 73%. Both large meta-analyses

demonstrate the CE capability and superiority.18

There are several capsules in use around the world. For example, the Given M2A imaging CE (Given

Imaging; Yokneam, Israel) is a pill-shaped capsule measuring 11 mm × 26 mm. Within the capsule, the

contents consist of a light source, an imaging chip, a battery source, and a radio transmitter with an

internal antenna. Its visual field is 140 degrees and is magnified 8 times. This capsule travels through

most of the small bowel with peristalsis and is excreted in the feces. The camera is able to take two

images every second and transmits image to an external recording device. The capsule has a battery life

lasting between 6 and 8 hours. At the completion of the study there are 50,000 images. There is

software available to help the interpreter evaluate for a suspected bleeding source. There is no

consensus on preprocedural bowel preparation, but some advocate for bowel prep. Prokinetics may be

beneficial because there is a 20% incomplete small bowel transit.19

SMALL BOWEL ENTEROSCOPY

The difficulty to evaluate the small bowel is based on its location and length. The scope needed to

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properly evaluate it is too long to have manual control of the tip. The bowel lies freely in the peritoneal

cavity with essentially no fixation. Navigation with an endoscope has been traditionally difficult for this

reason. Fixation points allow for proper evaluation of the foregut and colon in traditional endoscopy,

but this is not the case for small bowel. DE utilizes a fixation point provided by the scope and the small

bowel is brought to the viewing tip of the scope. Traditional endoscopy utilizes pushing the endoscope

through the gastrointestinal tract which is impossible without external intraoperative manipulation of

the bowel over the scope. Using this new method for evaluation has provided endoscopists with a steep

learning curve and added length of time to complete the evaluation.

5 The disadvantages of CE are difficulty with orientation, inability to biopsy, possible obstruction,

and capsule retention. Small bowel enteroscopy, DAE, or DE, are excellent alternative modalities.

DE allows the operator to obtain biopsies and to perform therapeutic interventions. There are three

methods for DE available today.

Double-Ballon Enteroscopy

This technique was developed in 2001 by Hironi Yamamoto,20 and introduced into Korea in 2004 where

it found its way to the United States. This endoscope consists of a balloon at the tip of an endoscope that

has a length of 140 cm. An overtube, also containing a balloon at the tip, fits over the scope to employ a

push-and-pull technique.21 This allows for examination of 240 to 360 cm. While the overtube balloon is

inflated, the scope is advanced with its balloon deflated. The inflated overtube balloon will allow for a

fixation point for the scope to maneuver through the small bowel. Once a significant advancement has

occurred, the endoscope balloon is inflated, and the overtube balloon deflated. The overtube then slides

along the endoscope to the end of the scope. The overtube balloon is reinflated to provide another

fixation point as the endoscope balloon is taken down and advanced once more. This outlines the push

technique as the endoscope is advanced with the overtube balloon inflated. The pull technique is when

both balloons are inflated and the endoscopist pulls back on both. This will reset the ability to start the

push technique again. This progression continues until the entire small bowel is evaluated.

The two most common enteroscope systems used have scope diameters of 8.5 mm and 9.3 mm with

working channels of 2.2 mm and 2.8 mm. The working channels allow for the therapeutic and

diagnostic options provided by these systems.

Double-balloon enteroscopy (DBE) is the most studied method to date and shows a diagnostic yield of

60% to 80% in patients with occult GI bleeding and other small bowel pathologies.22 However, it may

not be feasible in all patients and success rates vary from 16% to 86%.20,23 This variation is due to

differing patient populations across the world and the specific disease processes.

The main limitations to DBE are the invasive nature and prolonged duration of the procedure. The

complication rate overall is reported as 0.8% but can be higher while performing therapeutic procedures

such as electrocautery for a GI bleed, polypectomy, or dilation. The main complications are pancreatitis,

ileus, and perforation.24–26

Single-Balloon Enteroscopy

This system was developed in 2007 and is similar to DBE, but the distinguishing trait is that this system

lacks the endoscope balloon. There is still a balloon on the overtube used over the scope. Substituting in

the endoscope balloon’s place, the scope tip is hooked to hold the scope fixed to aid in the advancement

of the overtube. Overall, the concept is the same as to fix a portion of the small bowel to allow for

advancement of the endoscope.

The overtube is referred to as the splinting tube which has a hydrophilic coating that is activated with

application of 30 mL of water. Radiopaque material is present at the tip to aid in the advancement with

fluoroscopy.

Spiral Enteroscopy

Also in 2007, spiral enteroscopy (SE) was introduced which provides potential benefits with regard to

shorter procedure time. A raised spiral on the exterior of the scope pulls the small bowel over the scope

as it advances. This scope is 118 cm in length and has a diameter of 9.8 mm. The raised spiral grooves

are 16 mm high. Clockwise rotation of the scope will advance the scope and counterclockwise rotation

will withdraw the scope.

Studies for SE demonstrate shorter insertion depths with faster procedure times. There is variation in

the insertion depth varying from 176 cm to 262 cm.27,28 The complication rate is noted to be 0.3% with

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a perforation rate of 0.27%.22 Overall, the device is simple to use with a learning curve of 5 cases.22,29

Exploratory Laparoscopy

The role of laparoscopy has improved the management of small bowel lesions over the last decades.30,31

The advantages of DAE and imaging have been discussed at length, but the role for laparoscopic

assessment of the peritoneal cavity for small bowel tumors plays a significant role in both diagnosis and

treatment. Furthermore, the improvements in laparoscopy and surgeons abilities with a laparoscope

have enabled minimally invasive management of small bowel tumors. Johnson et al.32 evaluated all

small bowel obstructions in a single institution requiring surgery. Successful completion of a

laparoscopic approach was possible in 32% of patients (conversion to an open procedure was necessary

in 40% of patients, with 20% of the conversions secondary to tumor. Small bowel was resected in 8% of

the laparoscopic cases, 64% of the converted cases, and 41% of the case done completely open. Length

of stay of patients with a purely laparoscopic approach was 7.7 days versus 11 days in the converted

cases and 11.4 in the purely open cases.

There are distinct advantages to laparoscopy when the ability of the surgeon allows this approach.

Direct visualization of the small bowel on the extraluminal side adds significant value to the

management of small bowel tumors. Complete evaluation of the small bowel can be obtained

laparoscopically by examining the entire small bowel in a systematic approach in order to visualize all

aspects of the small bowel including the mesentery. In conjunction with endoluminal approaches, like

small bowel enteroscopy, lesions can be located, biopsied, and if needed, resected.

The laparoscopic approach is limited by the extent of the disease process being investigated. Local

spread of small bowel tumors will likely affect directly adjacent small bowel or other nearby organs.

This invasion can make it impractical to proceed laparoscopically if one is to provide the patient with

the best outcome. Also, most common tumors of the small bowel affect the mucosal surface only and

extraluminal visual examination may be inadequate to identify the lesion. Exceptions to this would be

utilizing small bowel enteroscopy to tattoo the lesion which can be easily seen from the extraluminal

side. This would also facilitate a sound oncologic resection of the tumor. Hand-assisted laparoscopy is

also helpful if palpation is essential and a small incision is desired.

A laparoscopic case should be converted to an open technique if conditions prevent oncologically

sound technique in order to provide the patient with the best outcome.

MANAGEMENT

Benign

Adenomas are benign lesions that have malignant potential. This tends to follow the malignant

degeneration seen in polyps of the large bowel, described in 1990,33 and most commonly seen with

periampullary tumors.34 Interestingly, the distribution of adenomas tends to follow the small bowel’s

exposure to bile, making the most common location immediately distal to the papilla in the second

portion of the duodenum and progressively decreases in the more distal intestine.35

Hamartomas are benign vascular tumors with a low malignant potential and usually associated with

Peutz–Jeghers syndrome.13 Lipomas are encountered as a single mass or as multiple and are usually

encountered incidentally. Hemangiomas are rare benign tumors in the small bowel that present as GI

bleeding.

The only reason for operative management of a benign small bowel lesion is to control symptoms.

Mass effect causing intussusception or obstruction, hemorrhage, or a questioned presence of malignancy

generates the need for local resection of the lesion. The diagnostic dilemma is the most common reason

for resection of an incidentally found mass on contrast study or endoscopy. Hemangiomatous lesions can

be resected or managed with angiographic embolization. The use of angiographic isolation and

intraoperative angiographic methylene blue injection can be very helpful to guide resection of a

bleeding field of small bowel angiomas.

Malignant

Discovery of small tumors is rare. Within the group of malignant tumors found in the small bowel, there

are four main types. The most recent data from a single-institution tumor registry show that carcinoid

tumors of the small bowel have surpassed the incidence for adenocarcinomas of the small bowel.1 A

total of 1,260 tumors were examined and their distribution throughout the small bowel was discussed.

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