Which one of the following hormones can induce neoplastic transformation of hypertrophied mammary tissue in cats?
Exogenous progesterone administration can lead to neoplastic transformation of mammary hyperplasia in intact or neutered male or female cats.
Patients undergoing progesterone therapy that develop mammary hyperplasia should have the enlarged mammary gland(s) removed and submitted for histology in addition to the cessation of progesterone therapy.
Refs: Johnston, Root Kustritz, and Olson's Canine and Feline Theriogenology, pp. 474-7 and Cote, Clinical Veterinary Advisor-Dogs and Cats, 3rd ed. pp. 631-3.