AIM: To assess the value of double-balloon enteroscopy (DBE) for the diagnosis of gastrointestinal mesenchymal tumors (GIMTs) in the small bowel and clarify their clinical and endoscopic characteristics.

METHODS: A retrospective review in a total of 783 patients who underwent a DBE procedure from January 2003 to December 2011 was conducted. Data from patients with pathologically confirmed GIMTs were analyzed at a single tertiary center with nine years’ experience. The primary outcomes assessed included characteristics of patients with GIMTs, indications for DBE, overall diagnostic yield of GIMTs, endoscopic morphology, positive biopsy, comparison of diagnosis with capsule endoscopy, and subsequent interventional management.

RESULTS: GIMTs were identified and analyzed in 77 patients. The mean age was 47.74 ± 14.14 years (range: 20-77 years), with 63.6% being males. The majority of individuals presented with gastrointestinal bleeding, accounting for 81.8%, followed by abdominal pain, accounting for 10.4%. Small bowel pathologies were found in 71 patients, the detection rate was 92.2%. The diagnostic yield of DBE for GIMTs was 88.3%. DBE was superior to capsule endoscopy in the diagnosis of GIMTs (P = 0.006; McNemar’s χ² test). Gastrointestinal stromal tumor was the most frequent and leiomyoma was the second frequent GIMT. Single and focal lesions were typical of GIMTs, and masses with smooth or unsmooth surface were the most common in the small bowel. GIMTs were removed from all the patients surgically except one patient treated with endoscopic resection.

CONCLUSION: DBE is a safe and valuable procedure for patients with suspected GIMTs, and it provides an accurate position for subsequent surgical intervention.

Small bowel diseases (SBDs) are less common in the entire digestive tract[1]. As a result of deep anatomical location of the small bowel (SB) and nonspecific clinical manifestations of SBDs, the diagnosis and management of SBDs are frequently delayed, leading to considerable medical cost and poor prognosis[2]. Early identification, diagnosis and intervention for SBDs become extremely important in clinical practice. With the development of capsule endoscopy (CE) and balloon-assisted enteroscopy (BAE), a new era has been created for the diagnosis of SBDs.

Gastrointestinal mesenchymal tumors (GIMTs), including myogenic tumors, neurogenic tumors and gastrointestinal stromal tumors (GISTs), account for less than 10% of gastrointestinal tumors[3-5]. Radiological imaging, such as barium study, computed tomography and angiography, is usually performed to examine GIMTs without the advent of CE and double-balloon enteroscopy (DBE). Traditional examination by barium study is feasible for biggish intraluminal SBTs[6,7]. CT is used to locate the lesion, assess for invasion and detect metastasis of SBTs[8,9]. Angiography is effective for detecting SBTs with active bleeding. GIMTs are common in the SB, varying from the duodenum to the ileum[10]. Their true incidences might be higher than those reported, as novel methods such as CE and BAE are much more sensitive and specific in diagnosing GIMTs than conventional methods[7]. CE is performed to detect SBTs and produce a higher detection rate due to its advantage of invasiveness[11-14].

Several studies reported DBE for the diagnosis of SBTs, indicating that DBE is a safe and effective procedure that enables accurate diagnosis of SBTs[15-19]. To date, few studies have reported the diagnosis of GIMTs by DBE and described their clinical and endoscopic features. This study was conducted retrospectively to evaluate the usefulness and safety of DBE for the diagnosis of GIMTs and to understand their clinical and endoscopic characteristics.

Since the introduction of CE and DBE, the blind spot of the entire GI tract has been revealed and investigated thoroughly. Our study reported the diagnosis of GIMTs using the DBE technique and their clinical characteristics. We analyzed the data of all the subjects registered in the DBE database in China, which represented more than 780 patients investigated by DBE for a variety of indications after the introduction of this modality. DBE produced a higher detection rate because GIMTs were diagnosed in 77 (9.8%) of 783 subjects who were suspected to have SBDs.

Other diagnostic modalities such as barium study and CT scan were used to detect SBTs prior to the introduction of CE and DBE. However, confirmative analysis is unfeasible for GIMTs. Moreover, surgical intervention should be performed cautiously in patients with indefinite diagnosis by these examinations. Small lesions are difficult to examine by these traditional examinations. DBE is performed to permit real-time visualization of the tumors and make a positional mark, which helps the surgeons to reveal the lesions. In our study, prior examinations only established clear diagnoses in a few patients. This may result in delayed interventions for GIMTs in patients with negative diagnoses. Most GIMTs in the small bowel may be malignant and invasive. Early detection and diagnosis of GIMTs using DBE would be conducive to early intervention and improvement of prognosis. Therefore, DBE is a reliable method as a complementary tool for traditional methods (such as barium meal and CT) or as a direct means for detecting GIMTs in the small bowel.

As a noninvasive and pain-free tool for investigating the small bowel, these advantages have made CE more competitive than DBE. Previous studies have shown that using CE to diagnose SBTs produced a higher accuracy in suspected patients[2,11,14,23]. Even though a small proportion of subjects received CE examinations before DBE, clear diagnosis for GIMTs established by CE was significantly lower than that by DBE in this study. This may be because of the nature of CE and confirmation of previous reports. CE is performed to visualize the GI tract according to bowel movement, this feature is both an advantage and a disadvantage. False positive or false negative findings for SBTs are the significant limitations of CE[24,25]. Missed diagnosis may occur during the examination because of only forward movement[26]. An intra-luminal tumor without mucosal damage or with less protuberance into the lumen is a significant challenge for CE to establish a clear diagnosis. In diagnosis of GIMTs in this study, CE failed to detect the presence of tumors in some patients. This shortcoming can be overcome by DBE through straightening the intestinal tube, which can reduce greatly the possibility of missed tumors. Moreover, severe complications, such as intestinal obstruction or CE retention, may occur during the procedure[27-31]. The most important aspect is that biopsy and histopathological establishment are unavailable for CE. These shortcomings of CE can be overcome by BAE.

Although previous studies have reported the diagnosis of DBE for SBTs and characterized the features of SBTs,[15,17-19,32] there are differences in distinct types of tumors arising from different tissues. Furthermore, a few patients with confirmed GIMTs were detected in these studies. The present study exclusively focused on the diagnosis and characteristics of GIMTs investigated by DBE. In theory, tumors from mesenchymal tissues have similar clinical and endoscopic characteristics. As reported in the literature[17-19,32], most SBTs are detected in adult patients and GI bleeding is a major indication for the DBE procedure. We found that patients with GIMTs were all adults. Males predominantly accounted for more than half of the patients. GI hemorrhage is the most frequent symptom of GIMTs. The main site of SBTs reported in the literature is the ileum[33]. Confirmed GIMTs from the current findings were almost exclusively located in the jejunum. Moreover, our rate of GIMTs (77/783) is higher than that previously reported[18]. In fact, GISTs represented 77.9% of GIMTs in our series. It is reported that this type of tumor is more frequently seen in the proximal small bowel[18,19].

We found that a single and focal lesion is typical of GIMTs, and that masses with a smooth or unsmooth surface are the most common in the small bowel. As far as GIMTs were concerned, precise diagnosis is readily concluded using the DBE procedure before histopathological analysis, which is judged by the endoscopic characteristics of GIMTs. According to our experiences and the findings of the present study, preoperative endoscopic diagnosis is consistent with the final histological diagnosis. As reported by Mitsui et al[18] 40.9% of patients with GISTs were positively diagnosed by the biopsy specimen. In our series, the rate of positive diagnosis by biopsy pathology was lower in patients with GIMTs (12.2%) than that reported previously. Biopsy diagnosis for GIMTs is not as effective as postoperative pathology of the excised specimen. Therefore, endoscopic diagnosis by BAE for GIMTs is effective and significant in clinical practice.

In conclusion, DBE is a safe and valuable procedure for patients with suspected GIMTs, and provides accurate position for subsequent surgical intervention.

We are grateful to our colleagues from the Department of General Surgery, Nanfang Hospital, Southern Medical University for their help with the study; and to the Department of Pathology, Nanfang Hospital, Southern Medical University for providing us the pathological images.