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