Endoscopic ultrasound (EUS) is a useful technology for the evaluation of diseases throughout the abdomen and mediastinum. In the colon and rectum it has clearly demonstrated utility in the locoregional staging of rectal carcinoma [
Relatively few reports of evaluation of colonic lesions by EUS miniprobes include examination of the appendix. Kameyama et al. included the description of a single appendiceal mucocele in a series of 46 cases (2.2%) [
A single academic center electronic endoscopy database review (Provation, Provation Medical, Minneapolis, MN) was performed for April 1, 2003 to February 29, 2008. A total of 2934 EUS cases were performed during the reviewed time period. Of those, 380 were characterized as lower EUS (13%). Additional cases were identified by searching the database for the use of a miniprobe EUS device. This allowed inclusion of cases that were logged as colonoscopy rather than EUS. Cases were selected if they were referred and evaluated for an appendiceal deformity found on endoscopy or subepithelial tumor versus extrinsic compression of the appendix. Procedure reports and images were reviewed. All cases were performed after a standard bowel preparation and used either a 12 MHz (model UM-2R) or 20 MHz mini probe (model UM-3R; Olympus America, Center Valley, PA) through the instrument channel of an adult or pediatric colonoscope. Visual inspection was followed by filling of the cecal base with sterile water. The miniprobe device was then advanced through the channel of the colonoscope and positioned adjacent to the lesion of interest. A full EUS evaluation was then performed and images captured.
Nine procedures were found to meet the inclusion criteria. The procedures were performed by one of two attending gastroenterologists. All but two included the participation of gastroenterology fellows. The cases were performed with moderate sedation using a mean of 131 mcg of fentanyl (range 100–200 mcg) and 3.67 mg of midazolam (range 2–5.5 mg). The mean age of the patients was 58 years (range 50–77). Seven (78%) were female. All were outpatients. Seven of the nine cases (78%) utilized the 12 MHz miniprobe device (Table
Patients and findings.
Case | Age | Gender | Device | Endoscopic finding | EUS findings | Surgery | Diagnosis | |||||
Size (mm) | Shape | Echotexture | Homogenity | Definition | Wall layer | |||||||
1 | 56 | Male | 12 MHz | Normal | No lesion | None | Normal | |||||
2 | 56 | Female | 12 MHz | Normal | No Lesion | None | Normal | |||||
3 | 55 | Female | 20 MHz | Erythema and small | No Lesion | None | Colitis | |||||
aphthoid ulcers around | ||||||||||||
appendiceal orifice | ||||||||||||
4 | 77 | Male | 12 MHz | Inverted appendix | Oval | Concentric | NA | Well defined | NA | None | Inverted | |
rings | Appendix | |||||||||||
5 | 50 | Female | 12 MHz | Submucosal mass | Round | Hypoechoic | Heterogenous | Well defined | Unclear | Laparoscopic right | Mucocele | |
hemicolectomy | ||||||||||||
6 | 60 | Female | 20 MHz | Appendix protuberant and | Round | Hypoechoic | Heterogenous | Well defined | Unclear | Laparoscopic | Mucocele | |
prominent | cecectomy | |||||||||||
7 | 63 | Female | 12 MHz | Submucosal mass | Oval | Anechoic with | Heterogenous | Well defined | Unclear | Open ileocecectomy | Mucocele | |
debris | ||||||||||||
8 | 51 | Female | 12 MHz | Submucosal mass | Oval | Hypoechoic | Homogenous | Well defined | Muscularis | None | Suspected | |
Mucosae | GIST | |||||||||||
9 | 56 | Female | 12 MHz | Submucosal mass | Round | Hyperechoic | Homogenous | Well defined | Submucosa | None | Lipoma |
The findings are summarized in Table
One case was found to be an inverted appendix. The endoscopic suspicion was confirmed by the EUS appearance of concentric rings made up of the mural layers of the appendix.
Three patients were referred to surgery based on the findings of the EUS. They each underwent ileocecectomy—one open and two laparoscopically—which removed mucinous cystadenomas, a type of mucocele. By EUS, they were described as anechoic to hypoechoic and heterogenous (Figure
Endoscopic, EUS, and radiographic images of appendiceal findings. (a) Endoscopic image of an appendiceal mucocele; (b) endosonographic image of an appendiceal mucocele; (c) CT scan image of an appendiceal mucocele (arrowhead); (d) endosonographic image of an appendiceal lipoma.
One case identified a
Finally, one lesion was described endoscopically as a medium-sized subepithelial mass at the appendiceal orifice. The sonographic appearance was hyperechoic, homogenous, and well defined. It originated within the submucosal layer. Based on these findings, it was felt to be most consistent with a lipoma (Figure
Complete endoscopic evaluation of the colon involves visualization of the base of the cecum and ostium of the vermiform appendix. Primary mucosal adenoma and adenocarcinoma of the appendiceal orifice may be diagnosed with standard endoscopy and biopsy [
A bulging or subepithelial lesion of the appendix may have multiple etiologies. In the present series, three appendiceal mucoceles were identified and subsequently referred for surgical management with pathologic confirmation. One lesion had a typical appearance with a 3 cm anechoic lesion with a papillary formation on the wall. Two other lesions were smaller in size (10 mm and 15 mm diameter) and had a hypoechoic and heterogenous appearance without a defined cystic space. Based upon these features, other lesions such as carcinoid could not be excluded preoperatively.
Appendiceal mucoceles may appear as smooth bulbous subepithelial lesions of the cecum with an impression formed by the appendiceal orifice [
Three patients had normal findings by endoscopy and EUS. These patients were stable and asymptomatic on clinical follow-up ranging from one to four years. An inverted appendiceal orifice—a nonpathologic finding—was seen in one patient in the series. This has been previously described by both virtual and standard colonoscopy [
One lesion had the sonographic appearance typical of a lipoma. The EUS characteristics of lipomas have been well described throughout the gastrointestinal tract. As for the lesion in this series, the location within the submucosa and its hyperechoic, homogenous appearance was sufficient to confidently make the diagnosis [
Appendiceal malignancies are very rare. None were seen in this case series. In a histopathological review of 2154 patients who underwent appendectomy over a 9-year period, 22 were found to have malignant appendiceal neoplasms [
Appendiceal carcinoid tumor most often presents as appendicitis. It is the most common type of appendiceal primary malignancy and is found in 0.3%–0.9% of patients undergoing appendectomy [
Our series of patients were referred specifically to evaluate abnormal findings of the appendix identified by colonoscopy. EUS evaluation of the appendix is feasible with standard miniprobe devices and may allow selection of those in need of surgical management. Miniprobe EUS is not technically difficult and may be performed by experienced endosonographers without significant additional training. Several patients in our series had benign findings by endosonographic evaluation and were followed clinically. Others were subsequently referred for surgical resection.
The authors would like to thank University of Maryland Medical Center.