Amy, Mast cell tumors are common in ferrets. These tumors are found on the skin as raised areas that can cause hair loss and pruritis (itchy skin). These tumors are not as aggressive as mast cell tumors of dogs and cats can be. Removal of the tumor is usually curative. There has been reports of mast cell tumors found concurrently with insulinomas of the pancreas. Although this colud be coincidence I would recommend pre-op bloodwork to check the glucose level. Dr. Weiss [log in to unmask] [Posted in FML issue 1086]