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Key takeaways

Uterine tumors in dogs are abnormal growths of cells found in the uterus.

  • Most uterine tumors are benign
  • The most common form is leiomyoma, a benign tumor that arises from uterine muscle cells
  • Uterine tumors rare and affect intact female dogs, especially when middle-aged to older
  • Uterine tumors are idiopathic and often present as asymptomatic
  • Clinical signs such as infertility and vaginal discharge may arise
  • Severity varies according to the size, location, and type of tumor
  • Uterine tumors can also lead to a predisposition for pyometra, a potentially life-threatening condition
  • Diagnosis involves a physical examination, bloodwork, abdominal imaging, and cytology and/or biopsy of the tissue mass
  • Typical treatment is surgery (ovariohysterectomy/spay)
  • Chemotherapy might also be needed in cases of malignant tumors
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A closer look: Uterine Tumors in Dogs

Uterine tumors are rare overall. They affect exclusively intact female dogs, particularly middle-aged to older ones.

Most uterine tumors are benign and the prognosis is generally good. The prognosis is guarded for malignant tumors that have spread from the uterus. Symptoms associated with uterine tumors indicate a veterinary exam is warranted.

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Risk factors

The symptoms and their severity differ according to the type, size, and location of the tumor.

Uterine tumors can also predispose female dogs to pyometra (pus in the uterus) which is a serious and possibly life-threatening condition.

Possible causes

As for most tumors, the cause of uterine tumors is mostly unknown.

It is thought to be caused by a mix of risk factors that can be genetic, environmental, or hereditary.

Main symptoms

The condition usually presents as asymptomatic. In some cases might present with:

  • Infertility
  • Vaginal discharge

Testing and diagnosis

Uterine tumors are often discovered during routine check-ups or exams for other conditions as they are most often asymptomatic.

The diagnostic process consists of a full physical examination, including bloodwork and abdominal diagnostic imaging (X-rays or ultrasound).

Cytology and a biopsy of the tissue are often also necessary to determine the type of tumor and its severity.

Steps to Recovery

The typical treatment is to surgically remove the uterus (ovariohysterectomy, or “spay”). With this surgical procedure, the tumors are completely removed and there is no risk of recurrence.

In the case of malignant tumors and metastasis, chemotherapy is often necessary along with surgical removal of affected tissues.

The prognosis varies according to the type, location, and size of the tumor.

About 85 to 90% of uterine tumors are benign leiomyomas for which the prognosis is excellent. For malignant tumors, the prognosis is guarded, especially if metastasis occurs.


Apart from surgery (ovariohysterectomy/spay) there are no other known means of prevention.

Uterine tumors are not contagious.

Is Uterine Tumors in Dogs common?

Uterine tumors are an overall rare condition in dogs. They only affect female dogs that have not been spayed.

Typical Treatment

  • Surgery (ovariohysterectomy/spay)
  • Chemotherapy


Malcolm Weir, DVM, MSc, MPH; Debbie Stoewen DVM, MSW, RSW, PhD; Christopher Pinard, DVM - Writing for VCA Animal Hospitals
No Author - Writing for Veterinary Society of Surgical Oncology
No Author - Writing for The National Canine Cancer Foundation
PetMD Editorial - Writing for PetMD

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