Unilateral fibroepithelial hyperplasia of the mammary gland in a goat.

A 2.5-year-old female Nubian goat was admitted because of a mass involving the right mammary gland. Ultrasonography and cytologic examination of the mass revealed a benign or hyperplastic condition. A right mastectomy was performed. Results of histologic and immunohistochemical tests indicated mammary fibroepithelial hyperplasia (fibroadenomatous change), which is a condition usually found in cats. The mammary mass had not redeveloped in the goat after 1 year.