Mammary gland hyperplasia is a benign condition in which an an excessive amount of tissue grows, resulting in enlarged masses in the mammary glands. This is primarily limited to young, sexually intact, cycling, or pregnant queens, but it can also affect cats of either gender after neutering, and cats of either gender that are on progestogen medication.
Your veterinarian will need to differentiate between several possibilities to arrive at a reliable diagnosis. Fluid will be expressed from the mammary gland for laboratory analysis, and a biopsy of the tissue may also be analyzed to determine the exact cause of the excessive tissue growth, and whether the growth is in fact, of a benign or malignant (cancerous) nature. Mastitis (infection of the mammary glands) can usually be ruled out based on the absence of symptoms, such as painful glands and fever, but the presence or absence of bacteria in the expressed fluid will definitively rule out infection.
If the enlargement is due to high levels of progesterone, the mass will diminish as the levels fall at the end of the false pregnancy or gestation. To lower progesterone levels permanently, a hysterectomy may be considered if fertility is not an issue. If the enlargement is related to the use of prescription progestogens, the mass will diminish when the medication is withdrawn.
Enlargement that occurs after neutering will resolve itself spontaneously. If your cat is uncomfortable, your veterinarian may prescribe progesterone receptor blockers, or prolactin inhibitors (a peptide hormone that is primarily associated with lactation).
The likelihood of recurrence in cats that are left intact is unknown, as is any correlation with other abnormal conditions of the reproductive tract.
The process of the maturation and release of eggs
The glands in female animals that are used to produce milk; also called the udder or breast
A compound made up of a group of amino acids; aids in the digestion of certain proteins
A hormone that is created at the time of pregnancy
A hormone involving the secretion of milk
Something that becomes worse or life threatening as it spreads
The formation and secretion of milk and the processes involved
The process of removing tissue to examine it, usually for medical reasons.
The period that an animal is pregnant in which the fetus develops from conception to birth
The hormones that stimulate growth of the body
Denotes an animal that is still able to reproduce or is free of cuts and scrapes
Not being able to cause harm; the opposite of malignant.