Abstract
A 10-y-old, 145-kg, pet Large Black domestic pig with a history of heart failure, which was unresponsive to furosemide, and an enlarged abdomen was submitted for postmortem examination. An 11-kg, pale-pink, firm, multinodular mass was found in the region of the right ovary. On histologic examination, the mass appeared to originate from the wall of the uterine tube; there was no evidence of metastasis. Histologically, the mass was a biphasic tumor of epithelial and spindle cells. The epithelium was proliferative, not trapped residual glands, and was randomly dispersed through the spindle cell population as clusters and tubules lined by a monolayer of cuboidal cells. The spindle cell population resembled a fibroma with abundant collagen. There were no mitotic figures in either of the neoplastic cell populations. The uterus had cystic endometrial hyperplasia. Based on the histologic and immunohistochemical findings, this case fulfills the criteria of an adenofibroma.