© Georg Thieme Verlag KG Stuttgart · New York
Bulge or mass? A diagnostic dilemma of capsule endoscopy
04. August 2008 (online)
Capsule endoscopy has revolutionized the diagnostic approach to small-bowel disease, but its true accuracy is still largely unknown and equivocal findings pose diagnostic dilemmas. As underlined at some international meetings dedicated to capsule endoscopy, the differential diagnosis of submucosal masses versus bulges may be challenging. This issue is particularly important bearing in mind that up to half of all small-bowel malignancies, such as gastrointestinal stromal tumors (GIST), neuroendocrine tumors, and lymphomas, arise from the submucosal layer of the intestinal wall, and have the endoscopic appearance of a submucosal mass  . In addition, further characterization of a bulge by insufflation, touch, and cleansing (usually performed in conventional endoscopy of the upper and lower gastrointestinal tract), is precluded at capsule endoscopy, and endoscopic sonography is not feasible in the small bowel.
To better distinguish bulges from masses, we attempted, for the first time, to define a bulge by morphologic criteria. A bulge was defined as a round, smooth, large-base protrusion in the lumen having: (i) an ill-defined boundary with the surrounding mucosa; (ii) a diameter larger than its height; (iii) a nonvisible lumen in the frames in which it appears; and (iv) an image lasting less than 10 minutes. The last criterion was adopted because a serious condition may underlie a regional transit abnormality . Changes in color, erythema, and signs of mucosal disruption (exudates, erosions, and ulcers) are highly suggestive of a neoplastic mass, and therefore, were not included in the criteria. A typical small-bowel bulge is shown and is compared with a submucosal mass in [Fig. 1].
Fig. 1 a Typical appearance of small-bowel bulge: round, smooth protrusion having an ill-defined boundary with the surrounding mucosa; note the diameter larger than its height. b Submucosal mass (gastrointestinal stromal tumor [GIST]); note the sharp boundary with the mucosa and the diameter equal to its height.
Adopting these criteria, we reviewed 246 complete small-bowel film segments from capsule endoscopies performed for various indications (obscure bleeding 74 %, suspected Crohn’s disease 13 %, others 13 %) and we found that images from seven out of 246 film segments, from as many patients (2.8 %), fulfilled the proposed criteria for a bulge; the patients’ features are summarized in [Table 1]. Prior to capsule endoscopy examination, each of these seven patients had undergone an extensive diagnostic investigation by upper and lower endoscopy, small-bowel series and/or enteroclysis, abdominal sonography, and computerized tomography, with inconclusive results. Except for the bulge, the small-bowel examinations were normal in all but two patients in whom angioectasias were found ([Table 1]; patients 5 and 6). Subsequent reading of the capsule endoscopy diagnostic report disclosed that in all but one patient (number 6), the bulge had been identified and indicated as an endoscopic finding of uncertain significance. During follow-up, five of these patients underwent laparotomy; four of them had peritoneal adhesions and a normal small bowel. Adhesiolysis was done with a good clinical outcome in all but one patient. Patient 7 underwent an unremarkable exploratory laparotomy with enterotomic intraoperative enteroscopy; at the outset, this patient had severe obscure overt bleeding, which remained unexplained at 22 months' follow-up. Finally, in two patients (5 and 6), who were both taking aspirin long-term for coronary artery disease and with obscure occult bleeding, the bleeding resolved after they stopped taking aspirin and no alarm symptoms had developed at follow-up at 29 and 31 months, respectively. The laparotomic finding of peritoneal adhesions in most patients with bulges suggests that bulge may be the luminal equivalent of viscus deformation caused by adhesions.
Our work indicates that simple morphologic criteria may help in the differential diagnosis between small-bowel bulges and submucosal masses. Small-bowel bulge seems to be uncommon and benign, but further prospective studies using a larger series are needed to confirm our findings and to assess the reliability, accuracy, and reproducibility of these criteria.
Table 1 Clinical details and outcome of patients in whom the criteria for bulge were fulfilled. Patient no. Age, years Sex Capsule endoscopy indication Comorbidity Capsule endoscopy diagnosis Interventions and findings Follow-up, months Outcome 1 57 M Abdominal pain – Normal Laparotomy; adhesions + adhesiolysis 15 Improved 2 38 F Suspect Crohn's disease – Normal Laparotomy; adhesions + adhesiolysis 18 Improved 3 50 M Suspect Crohn's disease Previous gastrectomy for peptic ulcer disease Normal Laparotomy; adhesions + adhesiolysis 24 Improved 4 49 F Abdominal pain – Normal Laparotomy; adhesions + adhesiolysis 20 Unchanged 5 70 F Obscure gastrointestinal bleeding (occult) Coronary artery disease Angioectasia Aspirin stopped 29 Improved 6 75 F Obscure gastrointestinal bleeding (occult) Coronary artery disease Angioectasia Aspirin stopped 31 Improved 7 52 M Obscure gastrointestinal bleeding (overt) Epilepsy Normal Laparotomy + intraoperative endoscopy; normal 22 No obscure gastrointestinal bleeding relapse
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C. M. Girelli, MD
Gastroenterology and Digestive Endoscopy Service
First Division of Internal Medicine
Busto Arsizio Hospital
Via Galilei, 4
21052 Busto Arsizio (VA)