Appendiceal mucocele and peritoneal inclusion cyst mimicking right adnexal masses: a diagnostic challenge in gynecologic practice

Mucocele of the appendix (MA) is an uncommon disease. Preoperative differential diagnosis of MA and a peritoneal inclusion cyst (PIC) from gynecologic diseases is still a challenge. We herein report a very rare case with MA and PIC. As far as we know, this is the first report of a case having MA and PIC found simultaneously at surgery. A 31-year-old woman complained of lower abdominal pain and high fever. Based on her symptoms and laboratory tests, pelvic inflammatory disease (PID) was considered to be the most probable diagnosis. She underwent antibiotics therapy and her conditions subsided. However, ascites reappeared in a month, and ultrasound and MRI demonstrated a right ovarian cyst and a suspected right hydrosalpinx. Laparotomy revealed large PIC and MA with normal bilateral adnexa. Patients with an adnexal mass or symptoms suggesting PID should be examined carefully considering such conditions in a daily gynecologic practice.