Mucinous borderline tumours of the ovary and the appendix: A retrospective study and overview of the literature

Objectives. Appendectomy is often recommended in patients with mucinous borderline ovarian tumours (mBOTs) based on studies suggesting that metastatic disease from a primary appendiceal tumour can mimic mBOT. The present study assessed the incidence of mucinous neoplasms in the appendix associated with the presence of mBOT. Methods. A retrospective cohort study was performed in two university hospitals in the Netherlands between 1990 and 2011. All patients with mBOT and/or a mucinous appendiceal tumour were included. Results. Of 127 patients included, 98 had a primary mBOT and 29 had a primary mucinous appendiceal tumour. In patients with a mBOT, the appendix was either removed at prior surgery (4%), resected as part of the staging procedure showing no pathological abnormalities (13%), described as normal and not resected (58%), or not described and not resected (25%). During a median follow-up period of 5 years (range 2-23), two patients developed a recurrence in which the appendix was not involved. In all patients with a primary mucinous tumour of the appendix, the appendix appeared abnormal at the time of surgery. Eight of these patients (28%) were diagnosed with invasive ovarian metastases. A review of the literature including the cases from this study identified 510 mucinous ovarian tumours with borderline features and 214 associated appendectomies, of which 4 (1.9%) contained a primary appendiceal malignancy. Conclusions. A thorough inspection of the appendix should be performed in patients with a mucinous ovarian tumour with borderline features. An appendectomy should only be performed when the appendix is macroscopically abnormal.