Animal Doctor provides mastectoMY SURGERY (mammary gland excision). We accept referrals and provide second opinions.

Description: Surgical excision of one or more of the mammary glands due to disease.

Symptoms & What to look for: Firm, nodular, various sized subcutaneous or cutaneous masses associated with the mammary glands. Possible leakage of discharge from the nipples. Possible ulceration of the mammary masses if large enough or they become traumatized. If you suddenly find a new mass associated with the mammary glands on your female dog, or nipple discharge, we recommend evaluation.

How does it happen? Female dogs that are not spayed are at high risk for a mammary tumor. The incidence of hormones every heat cycle predisposes them to cancer.

  • If your pet is spayed before her first heat the chances of a Tumor are 0%
  • If your pet is spayed after her first heat she has a 7% chance of developing a Mammary Tumor
  • If you pet is not spayed she has a 25% chance in her lifetime of having a mammary mass.
Animal Doctor Mastectomy


Animal Doctor Provider


Animal Doctor Mastectomy

What questions do we ask?

  • When did you first notice the mass?
  • Is your pet spayed? When did this occur?
  • If not spayed, when was the last time your pet was in heat?
  • Have you noticed any discharge from the nipple or the vaginal area?

What are the steps we take to treat your pet?

  • Assessment of all the mammary tissue. Often a mass that starts in one gland can spread to another.
  • We look to see how firm, large, and how attached to underlying tissue the masses are.
  • We may also want to take x-rays of the lungs to look for any spread of a tumor to that area. Malignant mammary tumors often metastasize (spread) to the lungs.

Animal Doctor Mastectomy Surgery

How do we arrive at a diagnosis and appropriate treatment plan

  • Once the histopathology is completed, we can discuss further treatment if indicated.
  • Surgical excision may be curative, or we may need to remove more tissue based on the histopathology report.
  • Occasionally referral to an oncologist is recommended.

Fine Needle Aspiration

  • Using a small needle we can aspirate cells for cytology that may tell us the type of mass. This may give some indication of malignancy, but some masses due not exfoliate (give good cell samples) well. Then a biopsy would be recommended.


  • If the mass is large, or difficult to excise, we often take a small sample of the tissue and send it to a pathologist for histopathology. This can give a diagnosis, and help formulate a treatment plan (surgical, medical).

Mastectomy Surgery

  • If the mass is painful, ulcerated, or growing rapidly we may recommend surgical excision, as 50% of all Mammary Masses are Malignant. The mass is sent to a pathologist at an outside lab, and will give us a diagnosis, prognosis, and surgical margins.

Spaying at the same time

  • Depending on the health and age of the patient, we often recommend spaying the pet at the time of the mastectomy. This helps prevent further tumor growth due to many mammary masses being driven by hormones.

What are the risks if mammary masses are left unmanaged?

  • If the mammary masses are left untreated, they can continue to grow and multiply, causing discomfort, swelling, leakage from the nipples, and ulceration. And if the mass(es) are malignant (cancerous), they can metastasize to the lymph nodes, and to internal organs, including the lungs, which could result in death.