A master of disguise: A rare case of renal solitary fibrous tumour

Solitary fibrous tumour (SFT) of the kidney is extremely rare, with fewer than 100 reported cases. We describe a 58-year-old male with a left renal mass, initially suspected as transitional cell carcinoma on CT urography. He underwent radical nephroureterectomy with bladder cuff excision. Histology revealed spindle cells in a collagenous stroma, and immunohistochemistry showed strong nuclear STAT6 positivity, confirming SFT. Postoperative recovery was uneventful, and the patient remains disease-free at six months. Renal SFT diagnosis relies on histopathology and immunohistochemistry, with complete surgical excision as the mainstay and long-term surveillance recommended due to recurrence risk.