Mammary tumors in dogs are potentially benign or malignant. They occur most commonly in non-spayed females or female that were spayed later in life.

• 乳腺肿瘤在犬类中既可能是良性的；亦可能是恶性的.；最常发于未绝育的母犬；或老龄时期才绝育的母犬