A 48-year-old female with a 9-year history of granulosa cell tumour presented with progression of a mass in the left flank after the recent gradual rise of her inhibin B levels. She had experienced multiple recurrences and had undergone multiple operations to resect previous tumour recurrences. Initial laparoscopy did not identify the most recent recurrent mass. MRI was repeated a month after the surgery; it confirmed the presence of the mass and demonstrated an increase in the size of the tumour. Owing to difficulties in finding the tumour, a CT-guided wire localization of the mass was performed immediately prior to a second elective laparoscopy, leading to successful removal of the recurrent granulosa cell tumour. We describe the use of a conventional localization wire under CT guidance to facilitate the resection of a unique retroperitoneal tumour. This case report discusses the current applications of the wire localization technique, the evolution of the hook wire system, the potential complications that may occur and the factors influencing the likelihood of success of wire localization in the retroperitoneal space.