DOGS · Condition guide
Mammary tumors in dogs: what real veterinary cases show
Mammary tumors in dogs are growths that develop in the mammary glands, similar to breast cancer in humans. They are one of the most common types of tumors in female dogs, especially those that are not spayed or were spayed later in life. These tumors can be benign (non-cancerous) or malignant (cancerous), and early detection is crucial for effective treatment.
Owners often first notice a lump or mass on their dog's belly, which can vary in size and feel. It's important to have any new lumps checked by a veterinarian as soon as possible, as early diagnosis and treatment can significantly improve the prognosis and outcome for the dog.
What vets typically check for
- Physical examination and palpation of the mammary glands.
- Fine needle aspiration or biopsy to determine if the tumor is benign or malignant.
- Imaging, such as X-rays or ultrasound, to check for metastasis.
- Blood tests to assess overall health and organ function.
- Surgical removal of the tumor, often followed by histopathology to guide further treatment.
Not a replacement for veterinary care. Use this to walk into the conversation prepared, not to self-diagnose.
Real cases from the veterinary literature
Peer-reviewed reports our semantic search surfaces for Canine mammary tumors. Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- First description of basaloid carcinoma of the canine mammary gland: case report
Arquivo Brasileiro de Medicina Veterinária e Zootecnia · BR
Two female dogs were diagnosed with a type of breast cancer called basaloid carcinoma after tumors were found in their mammary glands. Both dogs underwent surgery to remove the tumors, but tests showed that the cancer had spread to nearby lymph nodes, and one dog even had cancer in her lungs. The tumors were examined under a microscope, revealing specific cell patterns that con
- Transmural gastrointestinal stromal tumor of the mixed subtype in a canine: case report
Brazilian Journal of Veterinary Pathology · 2026 · BR
A 7-year-old dog was brought in with symptoms like vomiting, diarrhea, weight loss, and abdominal pain. After imaging tests, the vet discovered a tumor in the dog's cecum, which was confirmed through a biopsy. The tumor, a gastrointestinal stromal tumor (GIST), was about 7 cm in size and had specific cell characteristics that helped the vet identify it. Treatment options for GI
- Uterine Lithiasis associated with neoplasia in a female dog: case report
Arquivo Brasileiro de Medicina Veterinária e Zootecnia · 2026 · BR
A 10-year-old mixed-breed female dog was brought in because she was lethargic, had a swollen belly, and was experiencing vaginal discharge. After tests, the vet found she had an infection in her uterus (open pyometra) and two unusual stones inside it, along with signs of cancer. During surgery to remove her uterus and ovaries, the vet discovered the stones were made of struvite
- Invasive carcinoma of no special type with medullary pattern in the canine mammary gland: histopathological and immunohistochemical characterization.
Journal of comparative pathology · 2026 · Brazil
A 14-year-old female mixed-breed dog was brought in with a noticeable lump in her breast area. After examining the mass, the veterinarian found it to be a rare type of breast cancer called medullary carcinoma. The tumor had unusual cell characteristics and a significant immune response from T lymphocytes, which are a type of white blood cell. While the study highlights the impo
- Application of Preoperative Transarterial Chemoembolization Before Hilar Liver Tumour Resection in a Dog.
Veterinary medicine and science · 2026 · South Korea
A 12-year-old spayed female Beagle was diagnosed with a large liver tumor that was difficult to remove due to its location near major blood vessels. To make surgery safer, the vet used a treatment called transarterial chemoembolization (TACE), which shrank the tumor by 38% over four weeks. After the treatment, the dog had some mild discomfort but recovered well and underwent su
- Propranolol enhances the oncolytic effect of newcastle disease virus on canine mammary tumor cell by modulating the IFN-I-mediated JAK-STAT signaling pathway
Veterinary Quarterly · 2026 · GB
A study looked at how a combination of propranolol, a medication that can reduce immune responses, and Newcastle disease virus (NDV), which can kill cancer cells, might help treat canine mammary tumors in dogs. The researchers found that using propranolol with NDV improved the virus's ability to replicate and attack tumor cells in lab tests. In a model that mimicked canine mamm
Frequently asked questions
- What are the chances my dog's mammary tumor is cancerous?
- Approximately 50% of mammary tumors in dogs are malignant. Early detection and surgical removal can improve outcomes.
- Can mammary tumors spread to other parts of the body?
- Yes, malignant mammary tumors can metastasize to other organs, such as the lungs and lymph nodes, which is why early treatment is important.
- How can I prevent mammary tumors in my dog?
- Spaying your dog before her first heat cycle significantly reduces the risk of developing mammary tumors later in life.