Clinical characteristics and management of renal solitary fibrous tumors: a narrative review with literature-derived case evidence.

PURPOSE: Renal solitary fibrous tumor is a rare mesenchymal neoplasm with heterogeneous biological behavior. This review summarizes current evidence regarding its epidemiology, diagnosis, treatment, and clinical outcomes to support clinical management. METHODS: PubMed and Web of Science were searched from database inception to September 10, 2025, for studies involving renal solitary fibrous tumors. Eligible studies included case reports, case series, and original articles providing patient-level data on clinically and histologically confirmed primary renal solitary fibrous tumors. RESULTS: Renal solitary fibrous tumors commonly originate from the renal capsule or sinus and are frequently asymptomatic, although flank pain and hematuria may occasionally be present. Diagnostically, imaging typically reveals a well-circumscribed mass with variable enhancement patterns; however, histopathological examination remains essential for definitive diagnosis, characterized by spindle-cell proliferation and diffuse nuclear expression of STAT6. Therapeutically, complete surgical excision with negative margins constitutes the mainstay of treatment and is associated with favorable outcomes in the majority of patients. Nevertheless, approximately 10-15% of cases may develop recurrence or distant metastasis, underscoring the necessity of long-term surveillance. In the setting of advanced disease, limited data suggest that metastasectomy and selected targeted or anti-angiogenic agents may offer therapeutic benefit. CONCLUSION: Accurate diagnosis requires integrated clinical, radiologic, and pathologic evaluation. Complete resection remains the cornerstone of treatment, while prolonged follow-up is recommended because of the potential for delayed recurrence. Further molecular studies and collaborative investigations are needed to optimize risk stratification and therapeutic strategies.