We report the case of a patient affected by a voluminous prostatic tumor for which the histological analysis conclude in a stromal tumor of uncertain malignant potential. This type of tumor is rare, but requires to be individualized to differentiate it from a benign prostatic hyperplasia or a sarcoma of the prostate. The therapeutic care must be made keeping in mind the risk of degeneration towards a malignant shape. (C) 2014 Elsevier Masson SAS. All rights reserved.