Urinary and Pelvic Solitary Fibrous Tumors: A Study on 22 Patients

Background: Solitary fibrous tumors (SFT), most commonly found in the pleura, have a low incidence in the urinary and pelvic organs. This study aimed to discuss the diagnosis, treatment, and prognosis of urinary and pelvic SFT(UPSFT) as well as differences between benign and malignant UPSFTs. We aimed to gain a better understanding of this disease in the urinary and pelvic systems. Methods: Twenty-two patients with UPSFTs treated in our hospital between January 2004 and August 2021 were enrolled. General characteristics, clinical symptoms, imaging results, treatments, pathologies, and follow-up results were reviewed and analyzed. Results: Of the 22 patients, six (27.3%) showed non-specific clinical symptoms, including dysfunction of defecation, lower extremity weakness, urodynia, dysuria, frequent urination accompanied by changes in stool habits, low back pain, and abdominal wall mass with abdominal pain. Sixteen (72.7%) patients were asymptomatic. The median SFT diameter was 5.65 cm (range: 1.7–15 cm). All tumors were found to be space-occupying lesions on Doppler ultrasound, computed tomography, or magnetic resonance imaging. All patients were surgically treated, including nine, six, five, and two cases of robotic, open, laparoscopic, and transurethral resection of bladder tumor surgery, respectively. Pathology results revealed that frequent nuclear divisions, morphological variations, necrosis, and high expressions of Ki-67 were higher in malignant SFT compared with benign SFT. All patients were initially followed up 3 months post-surgery and every 6 months thereafter. Disease-free survival (DFS) in malignant SFT ranged from 5–63 months, with a median DFS of 37.0 months. Additionally, DFS was significantly longer in benign cases than that in malignant cases. Conclusions: UPSFTs do not typically present with specific clinical symptoms. Imaging exams were important in diagnosing UPSFT, with final diagnoses depending on histopathology results. In addition, surgical resection was the most common treatment with subsequent excellent prognoses, except in the case of malignancy.