Torsion of the Appendix Secondary to Appendiceal Mucocele

Abstract

Mucinous cystadenoma of the appendix, or the so-called appendiceal mucocele, is a rare disease entity 1 that has been infrequently diagnosed before surgery or autopsy because of its lack of specific diagnostic features. With the development of cross-sectional imaging techniques, including sonography and computed tomography, the number of reports describing preoperatively diagnosed cases has increased. 2-5 Most cases of this disease are clinically asymptomatic; however, on occasion, several complications may be associated with it, such as intussusception and, in the case of perforation, pseudomyxoma peritonei. Although mucoceles originating in the ovary may occasionally be complicated by ovarian or adnexal torsion, the torsion of an appendiceal mucocele is extremely rare. To our knowledge, 42 cases of torsion of the vermiform appendix have been reported in the literature; of these, only 6 cases were associated with an appendiceal mucocele. 6-11 We hereby present a case of torsion of the appendix that occurred secondary to an appendiceal mucocele that was diagnosed preoperatively by using gray scale and contrast-enhanced sonography. Preoperative gray scale sonography showed a targetlike appearance at the base of the appendix that indicated the presence of this disease condition. In addition, contrast-enhanced sonography was useful in evaluating the viability of the appendiceal wall. We present the sonographic findings of mucinous cystadenoma of the appendix with associated torsion and evaluate their correlation with surgical and pathologic findings.