Overtube-assisted enteroscopy and capsule endoscopy for the diagnosis of small-bowel polyps and tumors: a systematic review and meta-analysis

Small Bowel Tumors: A 7-Year Study in a Tertiary Care Hospital

(1) Background: Tumors of the small bowel represent 3-6% of gastrointestinal neoplasms and 3-6% of GI malignancies. The difficulties regarding the diagnosis are associated with larger tumors at the moment of the diagnosis and with advanced forms of malignant tumors, associated with a dismal prognosis. (2) Methods: We performed an observational, retrospective, cohort study that included patients with small bowel tumors admitted to the Craiova County Emergency Clinic Hospital between 1 January 2017 and 31 December 2023. The data were collected from the analysis of the patient's discharge documents from the Hippocrates computer system of the hospital and the evaluation of endoscopy databases. Patients under 16 years of age, those with no pathological confirmation of the malignancy, and those with insufficient data were excluded. (3) Results: A total of 80 cases of small bowel tumors were diagnosed; 72.5% were malignant, of which 10.3% were metastases. The most frequent primary malignant small bowel tumor was adenocarcinoma; two squamous cell carcinomas were noted. CT scans and upper digestive endoscopy represent the most frequent imaging methods for the diagnosis. The prognosis for malignant tumors was poor, with a 41% 5-year survival rate. (4) Conclusions: Small bowel tumors are rarely encountered, with 72.5% being malignant, and were diagnosed at large dimensions and in advanced stages for malignant tumors, with a dismal prognosis.

Small Bowel Lymphoma Complicated With Ischemic Colitis: A Case Report

Ischemic colitis is thought to be an injury to the colon as a result of reduced blood flow. Certain infectious diseases such as the Epstein-Barr virus can aid in the reduction of blood flow. The insult can range from inflammation and superficial injury to full-thickness necrosis. The typical regions affected are the "watershed" areas of the colon: the splenic flexure, the rectosigmoid junction, and the right colon. Because patients can present with a wide spectrum of symptoms from vague abdominal discomfort to complete abdominal catastrophe, the diagnosis of ischemic colitis is sometimes challenging to make. Patients typically present with the acute onset of crampy abdominal pain and usually pass blood mixed with stool within 24 hours. Endoscopically, ischemia is suspected in the presence of bluish hemorrhagic nodules from submucosal bleeding, cyanotic or necrotic mucosa with bleeding ulcerations, or a segmental distribution with an abrupt transition point between injured and normal mucosa. We present a case of an 80-year-old male with a history of hypertension, hyperlipidemia, and basal cell carcinoma of the scalp diagnosed with ischemic colitis associated with positive Epstein-Barr virus B cell lymphoma.

[Use of Device-Assisted Enteroscopy in Small Bowel Disease: An Expert Consensus Statement by the Korean Association for the Study of Intestinal Diseases]

The introduction of device-assisted enteroscopy (DAE) in the beginning of the 21st century has revolutionized the diagnosis and treatment of diseases of the small intestine. In contrast to capsule endoscopy, the other main diagnostic modality of small bowel diseases, DAE has the unique advantages of allowing the observation of the region of interest in detail and enabling tissue acquisition and therapeutic intervention. As DAE becomes an essential procedure in daily clinical practice, there is an increasing need for correct guidelines on when and how it is to be performed and what technical factors should be taken into consideration. In response to these needs, the Korean Association for the Study of Intestinal Diseases has developed an expert consensus statement on the performance of DAE by reviewing current evidence. This expert consensus statement particularly focuses on the indications, choice of insertion route, therapeutic intervention, complications, and relevant technical points.

Small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2022

MR1: ESGE recommends small-bowel capsule endoscopy as the first-line examination, before consideration of other endoscopic and radiological diagnostic tests for suspected small-bowel bleeding, given the excellent safety profile of capsule endoscopy, its patient tolerability, and its potential to visualize the entire small-bowel mucosa.Strong recommendation, moderate quality evidence. MR2: ESGE recommends small-bowel capsule endoscopy in patients with overt suspected small-bowel bleeding as soon as possible after the bleeding episode, ideally within 48 hours, to maximize the diagnostic and subsequent therapeutic yield.Strong recommendation, high quality evidence. MR3: ESGE does not recommend routine second-look endoscopy prior to small-bowel capsule endoscopy in patients with suspected small-bowel bleeding or iron-deficiency anemia.Strong recommendation, low quality evidence. MR4: ESGE recommends conservative management in those patients with suspected small-bowel bleeding and high quality negative small-bowel capsule endoscopy.Strong recommendation, moderate quality evidence. MR5: ESGE recommends device-assisted enteroscopy to confirm and possibly treat lesions identified by small-bowel capsule endoscopy.Strong recommendation, high quality evidence. MR6: ESGE recommends the performance of small-bowel capsule endoscopy as a first-line examination in patients with iron-deficiency anemia when small bowel evaluation is indicated.Strong recommendation, high quality evidence. MR7: ESGE recommends small-bowel capsule endoscopy in patients with suspected Crohn's disease and negative ileocolonoscopy findings as the initial diagnostic modality for investigating the small bowel, in the absence of obstructive symptoms or known bowel stenosis.Strong recommendation, high quality evidence. MR8: ESGE recommends, in patients with unremarkable or nondiagnostic findings from dedicated small-bowel cross-sectional imaging, small-bowel capsule endoscopy as a subsequent investigation if deemed likely to influence patient management.Strong recommendation, low quality evidence. MR9: ESGE recommends, in patients with established Crohn's disease, the use of a patency capsule before small-bowel capsule endoscopy to decrease the capsule retention rate.Strong recommendation, moderate quality evidence. MR10: ESGE recommends device-assisted enteroscopy (DAE) as an alternative to surgery for foreign bodies retained in the small bowel requiring retrieval in patients without acute intestinal obstruction.Strong recommendation, moderate quality evidence. MR11: ESGE recommends DAE-endoscopic retrograde cholangiopancreatography (DAE-ERCP) as a first-line endoscopic approach to treat pancreaticobiliary diseases in patients with surgically altered anatomy (except for Billroth II patients).Strong recommendation, moderate quality evidence.

Use of device-assisted enteroscopy in small bowel disease: an expert consensus statement by the Korean Association for the Study of Intestinal Diseases

The introduction of device-assisted enteroscopy (DAE) in the beginning of 21st century has revolutionized the diagnosis and treatment of diseases of the small intestine. In contrast to capsule endoscopy, the other main diagnostic modality of the small bowel diseases, DAE has the unique advantages of observing the region of interest in detail and enabling tissue acquisition and therapeutic intervention. As DAE becomes an essential procedure in daily clinical practice, there is an increasing need for correct guidelines on when and how to perform it and what technical factors should be considered. In response to these needs, the Korean Association for the Study of Intestinal Diseases developed an expert consensus statement on the performance of DAE by reviewing the current evidence. This expert consensus statement particularly focuses on the indications, choice of insertion route, therapeutic intervention, complications, and relevant technical points.

Risk for Surgery in Patients with Polyposis Syndrome after Therapy by Device-Assisted Enteroscopy (DAE): Long-Term Follow Up

BACKGROUND AND AIM OF THE STUDY

Polyposis syndromes such as Peutz-Jeghers (PJ) and familial adenomatous polyposis (FAP) are associated with the growth of small bowel polyps; the risk is approximately 60-90% for PJ and 40-70% for FAP. The primary aim of this study was to evaluate the efficacy of device-assisted enteroscopy (DAE) in the detection and treatment of small bowel polyps to reduce the risk of surgery. The secondary objective was to study complications and mortality.

METHODS

We conducted a retrospective cohort study by analyzing a structured database. Between September 2006 and October 2019, we observed and followed 42 consecutive patients with polyposis syndromes; they underwent device-assisted enteroscopy and three were excluded from elective surgery after the exam. The endoscopic exams were performed for diagnostic and therapeutic purposes.

RESULTS

Thirty-nine patients were evaluated with a mean follow up of 6.7 years (±SD 2.7), 79.5% were female with a mean age of 43.8 years (±SD 15.02), and 68 enteroscopies were performed with the removal of 64 polypoid lesions. One bleeding episode occurred after operative enteroscopy, and the need for subsequent surgery occurred in six patients with PJ and in five patients with FAP. The surgical indications in PJ patients were the presence of large polyps (three patients) and three cases of intussusception, one of which was a patient with a polyp in the proximal ileum, not reachable with the scope. One patient with PJ died from pancreatic cancer during follow up. The surgical indications in patients with FAP were the presence of four large polyps with high-grade dysplasia and one ampullary neoplasia recurrence.

CONCLUSIONS

In PJ patients, the endoscopic treatment of small bowel polyps was safe. During the follow-up period, the patients with successful endoscopic treatment did not need surgery. In FAP patients treated with DAE, none developed cancer.

Detection of polyps in the small bowel of patients with acromegaly via capsule endoscopy

BACKGROUND

the prevalence of small bowel (SB) polyps is unknown in acromegaly patients.

OBJECTIVE

to evaluate the prevalence of polyps/tumors in SB of acromegaly patients.

MATERIAL

this was a prospective and observational study that compared the prevalence of polyps/tumors using capsule endoscopy with a standard protocol in asymptomatic acromegaly patients and non-acromegaly patients, with abdominal pain, diarrhea or anemia.

RESULTS

one hundred and eighty-three cases were included (61 acromegaly and 122 non-acromegaly). Polyps were found in six (9.8%) and three (2.5%) patients, respectively (RR: 4 [95% CI, 1.03-15.45; p = 0.038]). There were no differences in the tumors (n = 4, 6.6% vs n = 7, 5.7%).

CONCLUSIONS

acromegaly may be associated with more polyps in SB.

Intra-operative enteroscopic polypectomy-An innovative hybrid approach using straight sticks

Background

Peutz-Jeghers Syndrome (PJS) is an uncommon intestinal polyposis disorder. Bowel obstructions are a recurring problem in PJS and as many as 50% of these patients require surgery. The current standard of care for these patients is to perform a flexible enteroscopic polypectomy. The traditional push-pull enteroscopy however, might be unavailable or unsuitable in an emergency setting. Alternatively, repeated laparotomies with multiple small bowel resections can lead to short bowel syndrome.

Methods

In our series, we describe an innovative technique where a short midline laparotomy permitted sufficient access to reduce the intussusception(s) and perform a bowel walk. Rigid laparoscopic instruments were introduced within the small bowel lumen via enterotomies, to perform polypectomies along the entire small bowel length. This precludes the need for small bowel resections which can thwart the development of short bowel syndrome.

Results

Two patients with PJS presenting with acute small bowel obstruction underwent surgery using the described approach. Another two patients with PJS having multiple intussusceptions on CT underwent an elective prophylactic polypectomy using the same approach. We were able to run the bowel in its entirety and a maximum of 41 polyps were retrieved from the port site enterotomy. The operating times were modest and no unique complications pertaining to this technique were encountered.

Conclusion

Small bowel polypectomy using rigid instrumentation employing a limited midline laparotomy is an attractive option for both emergency and elective settings in patients with PJS.

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Bowel obstructions are a recurring problem in PJS.

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Polypectomy using rigid instrumentation serves as an attractive option for patients with PJS, undergoing a laparotomy for acute bowel obstruction.

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This technique can be empolyed in both, elective as well as emergency settings.

Concordance between capsule endoscopy and device-assisted enteroscopy in small-bowel lesions

The agreement between capsule endoscopy (CE) and device-assisted enteroscopy (DAE) in tumors of the small-bowel (SB) may be high. However, other SB lesions such as ulcers and angioectasias seem to have more agreement between both procedures, compared to tumors or polyps. In the article published by Alventosa-Mateu C et al., an interesting case was presented of a patient with iron deficiency anemia secondary to two carcinoid ileum tumors, identified by CE and later biopsied and tattooed by DAE.

Small Bowel Enteroscopy - A Joint Clinical Guideline from the Spanish and Portuguese Small Bowel Study Groups

The present evidence-based guidelines are focused on the use of device-assisted enteroscopy in the management of small-bowel diseases. A panel of experts selected by the Spanish and Portuguese small bowel study groups reviewed the available evidence focusing on the main indications of this technique, its role in the management algorithm of each indication and on its diagnostic and therapeutic yields. A set of recommendations were issued accordingly.

Roles of Capsule Endoscopy and Device-Assisted Enteroscopy in the Diagnosis and Treatment of Small-Bowel Tumors

With the development of capsule endoscopy (CE) and device-assisted enteroscopy (DAE), the incidence of small-bowel tumors has increased and the characteristics of these tumors have changed. In addition, the diagnostic and therapeutic approaches for small-bowel tumors have diversified. CE is a simple, noninvasive method that aid in the visualization the entire small bowel. CE is considered the initial approach for small-bowel tumors. DAE can be used to perform endoscopic procedures such as bleeding control, polypectomy, stent insertion, and tattooing, as well as for diagnosis through visualization or tissue sampling. Therapeutic intervention with DAE is particularly useful in polyposis syndromes such as familial adenomatous polyposis and Peutz-Jeghers syndrome. This review will discuss the roles of CE and DAE in the diagnosis and treatment of small-bowel tumors.

Diagnostic agreement between video capsule endoscopy and single and double balloon enteroscopy for small bowel bleeding at a tertiary care hospital in Bogota, Colombia

INTRODUCTION

Video capsule endoscopy and balloon-assisted enteroscopy are complementary diagnostic methods in the study of small bowel bleeding, and different factors can affect their diagnostic yield.

AIMS

To define the level of agreement between video capsule endoscopy and enteroscopy in small bowel bleeding, according to the type of lesion, in a cohort of patients at a tertiary care referral center.

MATERIALS AND METHODS

A retrospective study was conducted that included 428 capsule endoscopies performed within the time frame of 2011 and 2019 at our healthcare institution. Seventy-four video capsule endoscopies, followed by enteroscopy, in 71 patients suspected of presenting with small bowel bleeding, were analyzed.

RESULTS

Mean patient age was 63.9 ± 13.5 years and 42 patients were women. The two diagnostic procedures were performed. Overall diagnostic yield of positive findings between video capsule endoscopy and enteroscopy was 86.5% vs. 58.1%, respectively (p = 0.0527). Agreement between video capsule endoscopy and enteroscopy for positive pathologic findings was weak (Ik = 0.17, 95% CI: -0.0097-0.3543), but according to lesion type, it was good for inflammatory lesions (Ik = 0.71, 95% CI: 0.5182-0.9119) and moderate for angiectasias (Ik = 0.45, 95% CI: 0.2469-0.6538) and tumors (Ik = 0.40, 95% CI: 0.1217-0.6794). The results between the two methods differed in 38 patients (51.3%). There was complete intestinal capsule retention in one patient (1.4%) and active bleeding in 13 (17.6%).

CONCLUSIONS

The present study showed that the two techniques had a similar overall detection rate for small bowel lesions, but the type of lesion was the main factor that could modify diagnostic agreement.

Small bowel enteroscopy - A joint clinical guideline by the Spanish and Portuguese small-bowel study groups

The present evidence-based guidelines are focused on the use of device-assisted enteroscopy in the management of small-bowel diseases. A panel of experts selected by the Spanish and Portuguese small-bowel study groups reviewed the available evidence focusing on the main indications of this technique, its role in the management algorithm of each indication, and its diagnostic and therapeutic yield. A set of recommendations was issued accordingly.

Predictors for finding lesions in the small bowel by enteroscopy after a positive capsule endoscopy

INTRODUCTION

studies have examined the agreement between capsule endoscopy and double-balloon enteroscopy, with varying results. The aim of this study was to identify factors that predict the visualization of lesions in the small bowel by double-balloon enteroscopy after a positive capsule endoscopy.

METHODS

a retrospective, observational and comparative study was performed that evaluated patients that underwent double-balloon enteroscopy after a positive capsule endoscopy, between January 2017 and August 2019. The data studied included demographics, indications, comorbidities and the results of capsule endoscopy and double-balloon enteroscopy, which were evaluated by multiple logistic regression.

RESULTS

91 patients were included (age 58 ± 16.5 years, 53 female). Sixty-two double-balloon enteroscopy (68.1 %) found the same lesions as capsule endoscopy. Predictive factors for a positive double-balloon enteroscopy were multiple lesions (OR 8.10, 1.50-43.78; p = 0.015) and < 15 days between both studies (OR 5.31, 1.19-23.66; p=0.029). In the subgroup of patients with small bowel bleeding (70 patients), the results of 46 double-balloon enteroscopies (65.7 %) agreed with the capsule endoscopy. Predictive factors in this group were multiple lesions (OR 13.51, 1.78-102.22; p = 0.012), < 15 days between both studies (OR 13.51, 1.78-102.22; p = 0.012), > 60 years of age (OR 7.45, 1.51-36.75; p = 0.014) and ulcers (OR 4.67, 1.08-20.22; p = 0.039).

CONCLUSIONS

predictive factors for a positive double-balloon enteroscopy after a positive capsule endoscopy were multiple lesions and < 15 days between both procedures. In patients with small bowel bleeding, age over 60 years and the presence of ulcers were also predictive factors.

Rare presentation of small bowel adenocarcinoma with neuroendocrine differentiation in the jejunum: A case report and summary of diagnostic and management options

Cancer of the small bowel (SB) is rare. The most common SB malignancy is neuroendocrine, followed by adenocarcinoma. SB adenocarcinoma with overlapping neuroendocrine differentiation (NED) is very uncommon. The present case report discusses the case of a young African American female who presented with high-grade SB perforation and underwent urgent surgical repair. Histology of the tumor revealed jejunal adenocarcinoma with NED. To the best of our knowledge, this type of tumor has not yet been reported in the jejunum. Referring patients that present with insidious and nonspecific abdominal discomfort for imaging studies that are more sensitive to the SB could potentially identify tumors earlier, prevent the development of emergent gastrointestinal complications and offer a chance for cure. An overview of diagnostic tools for SB evaluation was provided.

Video capsule endoscopy vs double-balloon enteroscopy in the diagnosis of small bowel bleeding: A systematic review and meta-analysis

AIM

To compare the diagnostic accuracy of video capsule endoscopy (VCE) and double-balloon enteroscopy (DBE) in cases of obscure gastrointestinal bleeding (OGIB) of vascular origin.

METHODS

MEDLINE (via PubMed), LILACS (via BVS) and Cochrane/CENTRAL virtual databases were searched for studies dated before 2017. We identified prospective and retrospective studies, including observational, cohort, single-blinded and multicenter studies, comparing VCE and DBE for the diagnosis of OGIB, and data of all the vascular sources of bleeding were collected. All patients were subjected to the same gold standard method. Relevant data were then extracted from each included study using a standardized extraction form. We calculated study variables (sensitivity, specificity, prevalence, positive and negative predictive values and accuracy) and performed a meta-analysis using Meta-Disc software.

RESULTS

In the per-patient analysis, 17 studies (1477 lesions) were included. We identified 3150 exams (1722 VCE and 1428 DBE) in 2043 patients and identified 2248 sources of bleeding, 1467 of which were from vascular lesions. Of these lesions, 864 (58.5%) were diagnosed by VCE, and 613 (41.5%) were diagnosed by DBE. The pretest probability for bleeding of vascular origin was 54.34%. The sensitivity of DBE was 84% (95%CI: 0.82-0.86; heterogeneity: 78.00%), and the specificity was 92% (95%CI: 0.89-0.94; heterogeneity: 92.0%). For DBE, the positive likelihood ratio was 11.29 (95%CI: 4.83-26.40; heterogeneity: 91.6%), and the negative likelihood ratio was 0.20 (95%CI: 0.15-0.27; heterogeneity: 67.3%). Performing DBE after CE increased the diagnostic yield of vascular lesion by 7%, from 83% to 90%.

CONCLUSION

The diagnostic accuracy of detecting small bowel bleeding from a vascular source is increased with the use of an isolated video capsule endoscope compared with isolated DBE. However, concomitant use increases the detection rate of the bleeding source.

Risk factors for advanced duodenal and ampullary adenomatosis in familial adenomatous polyposis: a prospective, single-center study

BACKGROUND AND STUDY AIMS

 To determine the clinical features associated with advanced duodenal and ampullary adenomas in familial adenomatous polyposis. Secondarily, we describe the prevalence and clinical significance of jejunal polyposis.

PATIENTS AND METHODS

 This is a single center, prospective study of 62 patients with familial adenomatous polyposis. Duodenal polyposis was classified according to Spigelman and ampullary adenomas were identified. Patients with Spigelman III and IV duodenal polyposis underwent balloon assisted enteroscopy. Predefined groups according to Spigelman and presence or not of ampullary adenomas were related to the clinical variables: gender, age, family history of familial adenomatous polyposis, type of colorectal surgery, and type of colorectal polyposis.

RESULTS

 Advanced duodenal polyposis was present in 13 patients (21 %; 9 male) at a mean age of 37.61 ± 13.9 years. There was a statistically significant association between family history of the disease and groups according to Spigelman ( P  = 0.03). Seven unrelated patients (6 male) presented ampullary adenomas at a mean age of 36.14 ± 14.2 years. The association between ampullary adenomas and extraintestinal manifestations was statistically significant in multivariate analysis ( P  = 0.009). Five endoscopic types of non-ampullary adenoma were identified, showing that lesions larger than 10 mm or with a central depression presented foci of high grade dysplasia. Among 28 patients in 12 different families, a similar Spigelman score was identified; 10/12 patients (83.3 %) who underwent enteroscopy presented small tubular adenomas with low grade dysplasia in the proximal jejunum.

CONCLUSIONS

 Advanced duodenal polyposis phenotype may be predictable from disease severity in a first-degree relative. Ampullary adenomas were independently associated with the presence of extraintestinal manifestations.

Efficacy of double-balloon enteroscopy for small-bowel polypectomy: clinical and economic evaluation

BACKGROUND

We evaluated first the feasibility of endoscopic small-bowel polypectomy and second, the economic aspects, by comparing the cost of endoscopic and surgical polyp resection.

METHODS

A prospective, observational, multicenter study included 494 patients with positive capsule endoscopy (CE) before double-balloon enteroscopy (DBE). We selected only CE with at least one polyp. The retrospective economic evaluation compared patients treated by DBE or surgery for small-bowel polypectomy. Hospital readmission because of repeat polyp resection or complication-related interventions was noted. The 1-year cost was estimated from the viewpoint of the healthcare system and included procedures, hospital admissions and follow up.

RESULTS

CE indicated one or more polyps in 62 (12.5%) patients (32 males, 49 ± 5 years), all of whom underwent a successful DBE exploration. The DBE polyp diagnostic yield was 58%. There were no major complications. A total of 26 (42%) patients in the DBE group and 19 (39%) in the control group required hospital readmission. All readmissions in the DBE group were for repeat procedures to remove all polyps, and in the control group, for surgical complications. The total cost of the initial hospitalization (€4014 ± 2239 DBE versus €11,620 ± 7183 surgery, p < 0.0001) and the 1-year total cost (€8438 ± 9227 DBE versus €13,402 ± 7919 surgery, p < 0.0001) were lower in the DBE group.

CONCLUSIONS

Endoscopic polypectomy was efficient and safe. The total cost at 1 year was less for endoscopy than surgery. DBE should be proposed as the first-line treatment for small-bowel polyp resection.

An update on small bowel endoscopy

PURPOSE OF REVIEW

The breakthrough success of capsule endoscopy and device-assisted enteroscopy has inspired researchers to test and push the boundary of these technologies. The authors herein summarize the latest and most significant studies with clinical impact.

RECENT FINDINGS

Competing capsule endoscopy models have enriched the platform of this wireless device. The role of capsule endoscopy in Crohn's disease is expanding as we learn more of the significance of disease distribution and response to treatment. The benefit of capsule endoscopy in abdominal pain has previously been sceptical, but may have a role. Device-assisted enteroscopy demonstrates significant benefit in the management of patients with Crohn's disease and Peutz-Jeghers syndrome. On the contrary, long-term data suggest that endotherapy to small bowel angioectasia may not be as beneficial to patients as we once thought. The role of device-assisted enteroscopy in novel territory, including coeliac disease and endoscopic retrograde cholangiopancreatography, continues to be tested.

SUMMARY

The limit of capsule endoscopy and enteroscopy is yet to be reached. Accumulating long-term data alludes to the benefits of our current practice while spawning novel indications for small bowel endoscopy.

Neoplastic Diseases of the Small Bowel

The incidence of small bowel tumors is increasing over time. Until recently, their diagnosis was delayed and it was often reached only at the time of surgery. New diagnostic tools, such as capsule endoscopy, device-assisted enteroscopy, and dedicated small bowel cross-sectional imaging techniques, have been introduced recently in clinical practice. The combination of these tools allows medical practitioners to detect small bowel tumors at an early stage and to reach a definite diagnosis before surgery, thus enabling minimally invasive treatments.