Surgical resection using retroperitoneal approach for solitary fibrous tumor in the pelvis.

This report concerns a case of solitary fibrous tumor (SFT) for which surgical resection was performed using a retroperitoneal approach. A 41-year-old man was referred to our hospital with urinary retention. Abdominal ultrasound sonography (US) and computed tomography (CT) showed a hypervascular mass lesion in the pelvis. Transrectal biopsy showed SFT. Surgical resection was carried out using a retroperitoneal approach and preserving the neural network related to urinary and erectile functions. Based on immunohistochemical findings, the tumor was diagnosed to be malignant SFT in the pelvic cavity. Urinary function improved post-operation. There was no change to IIEF-5 and it continued to function well. The patient showed no sign of recurrence 12 months after surgery and required no additional therapy.