Suprarenal solitary fibrous tumor associated with a NF1 gene mutation mimicking a kidney neoplasm: implications for surgical management.

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm, usually occurring in the pleura. Pararenal SFT, mimicking an adrenal gland or renal tumor, as here described, is extremely rare. We report a case of a right suprarenal SFT, incidentally discovered by abdominal ultrasound in a 54-year-old woman carrying a point neurofibromatosis 1 (NF1) gene mutation. Preoperative diagnostic work-up was ineffective in evaluating its origin, and an open radical right nephrectomy was therefore undertaken. Immunohistochemical assay showed a positivity for CD34, CD99 and Bcl-2, so suggesting a diagnosis of SFT. According to our knowledge, the association between this type of tumor and NF1 gene mutation has never been described. In cases of pararenal tumors, a more detailed preoperative diagnosis could be useful to better plan the extension of resection, allowing, in selected cases, nephron-sparing surgery. More studies are needed to better analyze the relationship between NF1 gene mutation and SFT.