Serosal Inclusion Cysts and Arteriovenous Fistulas in Paraprostatic Area of a Dog

Abstract

Multiple cysts and mass lesions were detected adjacent to the prostate of a 14-year-old, male, mixed breed dog with a history of perineal hernia. Histologically, the cysts were lined by epithelial cells with microvilli. The masses were mainly composed of thin walled venous and/or lymphatic structures, and partially thickened wall artery-like structures. The epithelial cells of cysts were positive for antibodies against cytokeratin AE1/AE3, CAM5.2, vimentin and Wilms' tumor protein, and the endothelial cells of masses were positive for antibodies against CD31 and factor VIII by immunohistochemical analysis. By Elastica van Gieson staining, elastic fibers were seldom observed in the thickened vascular walls, which mainly consisted of collagen fibers and muscle tissue. Based on these findings, the diagnosis was made of serosal inclusion cysts and arteriovenous fistulas in the paraprostatic area of a dog.