I recently had a ferret come into our shelter with one of these preputial masses. Unfortunately, the outcome was not good. The diagnosis was apocrine adenocarcinoma, and the little guy went into heart failure under anesthesia. Necropsy showed that most of his organs were already affected. Hopefully your outcome is better. Bonnie Tormohlen/Director California Domestic Ferret Educational Alliance Northern Arizona Ferret Alliance & Rescue, Inc [Posted in FML 6972]