Ovarian Tumors in Dogs

Ovarian Cysts in Dogs

There are three kinds dog ovarian tumors: epithelial tumors (skin/tissue), germ cell tumors (sperm and ova), and stromal tumors (connective tissue). The most common type of ovarian tumor in dogs is ovarian carcinomas. Granulosa cells are follicular cells (hollow cells) surrounded by theca cells (which form a surrounding sheath). Ovarian tumors are prone to metastasizing (spreading), and some are capable of producing hormones.

The tumors described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.

Symptoms and Types

  1. Fluid build-up in the abdominal cavity
  2. Fluid build-up in the chest cavity
  3. Tumors producing steroid hormone:
    • Lack of sexual heat and menstruation
    • Persistent estrus (menstruation and heat)
    • Pyometra (pus-filled abdomen)
    • Gynecomastia (male animal exhibits feminine traits, like having enlarged nipples with leaking milk)
    • Bilateral, symmetrical baldness
    • Masculinization (excess testosterone)



This condition is often associated with non-spayed and non-neutered dogs.


Your veterinarian will perform a thorough physical exam on your dog, including a blood chemical profile, a complete blood count, an electrolyte panel and a urinalysis. You will need to give your doctor a thorough history of your dog’s health, with a description of the onset of symptoms. X-rays may reveal the spread of cancerous cells (metastases) by way of the blood vessels or lymphatic system.

Your veterinarian will also take X-rays and ultrasound images of the abdomen and chest to look for further evidence of tumors. Abdominal X-rays might show a unilateral or bilateral mid-abdominal mass near the kidney, or fluid build-up in the abdominal cavity. An ultrasound of the abdomen can reveal similar information, but with even greater sensitivity and detail. If there is excess fluid in the pleural (chest) lining, or fluid in the abdomen, your veterinarian will take a fluid sample for microscopic (cytologic) examination.

If the size of the tumor is minor, and the growth minimal, your veterinarian may recommend surgery to remove a solitary tumor, or to take a tissue sample (biopsy) of the tumor. Even if a tumor appears to be obviously malignant, and is metastasizing (growing), a biopsy can still be invaluable for the final, definitive diagnosis.

Your veterinarian may also want to perform a procedure called a histopathologic examination, for tracking changes in the tissue, to better understand the character of the growth.


The disappearance of the signs and symptoms of a particular disease; this is often used in association with cancer


A product made of fluid, cell waste, and cells


The prediction of a disease’s outcome in advance


The sex cell of male animals; created in the testicles


The term for a type of medication that impacts immunity, metabolism, sexual characteristics, and other such elements of a living thing


An in-depth examination of the properties of urine; used to determine the presence or absence of illness


A condition of having only one side


The word for female eggs


Anything pertaining to the blood vessel system in the body


The process of removing tissue to examine it, usually for medical reasons.


Having two sides


Not being able to cause harm; the opposite of malignant.


The time period in which a female is receptive to male attention


Any micro organism with pathogenic capabilities, like a bacteria or virus

abdominal cavity

The space in the abdomen that holds the major digestive organs in an animal. Normally referred to as the area between the diaphragm and the pelvis. Also referred to as the peritoneal cavity.


Something that has to do with changes in the structure of the body as the result of cells that are diseased or abnormal in some way


Something that becomes worse or life threatening as it spreads

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