On cytology, the fluid was moderately cellular, primarily consisting of neutrophils with rare clusters of epithelial cells. No bacteria were seen on cytology, and no organisms were cultured from the fluid. Histologically, the tissue was composed of a dense band of fibrous connective tissue covered by a nonkeratinized stratified squamous epithelium. It contained a medium-sized blood vessel and several smaller blood vessels that were surrounded by rare neutrophils. Findings were consistent with the hymen of a nonpregnant mammal. After recovery, the dog’s dysuria, pollakiuria, and perineal swelling resolved. The dog was discharged with instructions to complete the previously prescribed course of marbofloxacin. At follow-up 2 months later, the dog was clinically normal.