What you see might not be what you get: Discrepancies between intraoperative findings and preoperative diagnosis of ovarian tumors. Appendicular mucocele presenting as an adnexal mass - Case report and review of literature.

INTRODUCTION: Adnexal masses include those affecting the ovary or fallopian tubes. We report a unique case with discrepancy between the pre-operative diagnosis (adnexal mass) and the post-operative definitive findings (appendicular tumor invading ovary). We also employ a literature review to provide four scenarios of uncertainty that are encountered between appendiceal and adnexal masses.

PRESENTATION OF CASE: A 58 year old female with history of treated left colon cancer, referred to the gynecology clinic with intermittent vaginal bleeding for 5 days. Examination showed lower abdominal midline mobile non-tender mass, bulky uterus and right adnexal fullness. Other history, physical examination and laboratory tests were unremarkable. US and MRI suggested a right ovarian mass and uterine fibroids. Intraoperatively, she had a right ovarian large mobile multi-locular mass. The appendix was adherent to the ovary, with mucus extruding through its tip. Appendectomy was undertaken alongside hysterectomy and bilateral salpingo-oophorectomy. Histopathology showed right ovarian mucinous neoplasm, but the origin was a low-grade appendiceal mucinous neoplasm (pT4aNxMx). The patient was recurrence free across 3 years of follow up.

DISCUSSION: Appendicular mucocele can present as adnexal mass. Pre-operative diagnosis and differentiation is sometimes difficult.

CONCLUSION: Adnexal masses need careful pre-operative diagnoses. The definitive management is based on the final intra- and post-operative findings. As a variety of scenarios could be encountered, there could be a need to involve general/colorectal surgeons in case of appendicular tumors. Patients should be counselled regarding the possible change in intra-operative plan, and are better operated upon in facilities with appropriate teams and equipment.