Bulge or mass? A diagnostic dilemma of capsule endoscopy

Capsule endoscopy has revolutionized the diagnostic approach to small−bowel disease, but its true accuracy is still large− ly unknown and equivocal findings pose diagnostic dilemmas. As underlined at some international meetings dedicated to capsule endoscopy, the differential di− agnosis of submucosal masses versus bulges may be challenging. This issue is particularly important bearing in mind that up to half of all small−bowel malig− nancies, such as gastrointestinal stromal tumors (GIST), neuroendocrine tumors, and lymphomas, arise from the submuco− sal layer of the intestinal wall, and have the endoscopic appearance of a submuco− sal mass [1,2]. In addition, further charac− terization of a bulge by insufflation, touch, and cleansing (usually performed in conventional endoscopy of the upper and lower gastrointestinal tract), is pre− cluded at capsule endoscopy, and endo− scopic 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 sur− rounding 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 [3]. Changes in color, erythema, and signs of mucosal disrup− tion (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 submuco− sal mass in l" Fig. 1. 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 %, oth− ers 13 %) and we found that images from seven out of 246 film segments, from as many patients (2.8%), fulfilled the pro− posed criteria for a bulge; the patients’ features are summarized in l" Table 1. Prior to capsule endoscopy examination, each of these seven patients had under− gone an extensive diagnostic investiga− tion by upper and lower endoscopy, small−bowel series and/or enteroclysis, abdominal sonography, and computer− ized tomography, with inconclusive re− sults. Except for the bulge, the small− bowel examinations were normal in all but two patients in whom angioectasias were found (l" Table 1; patients 5 and 6). Subsequent reading of the capsule endos− copy diagnostic report disclosed that in all but one patient (number 6), the bulge had been identified and indicated as an endoscopic finding of uncertain signifi− cance. During follow−up, five of these pa− tients underwent laparotomy; four of them had peritoneal adhesions and a nor− mal small bowel. Adhesiolysis was done with a good clinical outcome in all but one patient. Patient 7 underwent an un− remarkable exploratory laparotomy with enterotomic intraoperative enteroscopy; at the outset, this patient had severe ob− scure overt bleeding, which remained un− explained at 22 months’ follow−up. Final− ly, in two patients (5 and 6), who were both taking aspirin long−term for coron− ary artery disease and with obscure oc−