Appendiceal carcinoma presenting as an adnexal mass

Primary mucinous adenocarcinomas of the appendix represent <1% of all intestinal malignancies. As a group, these tumors are important because they are rarely diagnosed before surgery. A 34-year-old nulliparous white woman with a history of oligomenorrhea and primary infertility presented with a hypoechoic right adnexal mass found on transvaginal sonography, Surgical intervention revealed an appendiceal carcinoma. Although appendiceal carcinomas are rare in women of reproductive age, sonographic landmarks may be helpful in distinguishing these tumors from adnexal masses.