Abstract: | Solitary Fibrous Tumors (SFT) are rare spindle cell neoplasm that typically originate from the pleura. However, cases of the SFT are described with origin in other organs, including the urinary and genital apparatus. Within the kidney, except from the renal pelvis, only 19 cases of SFT are described and such rarity of localization makes the histogenesis and the prognosis of the tumor rather unknown. We report the case of a 72-year-old lady who attended our Unit for a mass that was clinically palpable at the level of the left hemiabdomen. The tomodensitographic test indicated a 19cm-diameter mass of likely pertinence of the middle bystender of the left kidney. She had undergone left radical nephrectomy. The histological examination highlighted a solitary fibrous tumor (SFT): the presence of hypercellularity, of cellular pleiomorphism and of a high number of mitosis has led to a histological diagnosis of malignancy for the neoplasm analyzed. The SFT are of rare clinical comparison: this does not allow for a deep knowledge of the lesion histogenesis and prognosis; moreover, the clinical behavior should be more precisely defined. |