[Aggressive fibromatosis (desmoid tumor) : A rare differential diagnosis of metastasis of renal cell carcinoma].

We report the case of a 65-year-old woman with an aggressive fibromatosis of the rectus abdominis muscle suspicious for a metastasis of renal cell carcinoma after tumor nephrectomy 3 years previously. Aggressive fibromatoses (desmoid tumors) are rare semimalignant tumors of the connective tissue with local infiltration and destruction of tissue. Complete resection is essential to avoid tumor relapse. Aggressive fibromatosis must be considered in the differential diagnosis of renal cell carcinoma metastasis. Complete resection and subsequent radiotherapy seem to be the therapy of choice.