Ovarian Cysts in Dogs
Dogs can develop three types of ovarian tumors: epithelial tumors (affecting skin or tissue), germ cell tumors (related to sperm and ova), and stromal tumors (involving connective tissue). Among these, ovarian carcinomas are the most prevalent in dogs. Granulosa cells, which are surrounded by theca cells forming a sheath, are commonly involved. Ovarian tumors in dogs have a tendency to spread (metastasize) and some have the capability to produce hormones.
These types of tumors are also observed in cats, as described in this medical article.
Symptoms and Types
Accumulation of fluid in the abdominal cavity
Accumulation of fluid in the chest cavity
Tumors producing steroid hormones may lead to:
- Absence of sexual heat and menstruation
- Prolonged estrus (menstruation and heat)
- Pyometra (abdomen filled with pus)
- Gynecomastia (male animals exhibiting feminine traits such as enlarged nipples with milk discharge)
- Bilateral, symmetrical baldness
- Masculinization (excessive testosterone levels)
Causes
This condition frequently occurs in dogs that have not been spayed or neutered.
Diagnosis
Your veterinarian will conduct a comprehensive physical examination of your dog, which includes obtaining a blood chemical profile, a complete blood count, an electrolyte panel, and a urinalysis. Providing a detailed history of your dog’s health, along with the onset of symptoms, is essential. X-rays may help identify the spread of cancer cells (metastases) through blood vessels or the lymphatic system.
Additionally, your veterinarian will utilize X-rays and ultrasound imaging of the abdomen and chest to detect potential tumors. Abdominal X-rays might reveal a mid-abdominal mass near the kidney, or fluid accumulation in the abdominal cavity. Abdominal ultrasound offers even greater sensitivity and detail. If there’s excess fluid in the chest lining or abdomen, your veterinarian will extract a fluid sample for microscopic examination (cytology).
For smaller tumors or minimal growth, your veterinarian might suggest surgery to remove a solitary tumor or to obtain a tissue sample (biopsy). Even if a tumor seems clearly malignant and is spreading, a biopsy remains invaluable for a definitive diagnosis.
Your veterinarian might also recommend a histopathologic examination to monitor tissue changes and better understand the nature of the growth.
Treatment
Surgical removal of a single tumor is often sufficient and typically does not necessitate an extended stay in the veterinary hospital. While benign tumors are uncommon, there are instances where they occur, and dogs with such tumors usually recover well. This holds true especially when a malignant tumor is identified and treated before it spreads.
Chemotherapy can be employed to treat a malignant tumor that has metastasized, potentially halting its growth, inducing remission, and occasionally achieving a cure. However, the prognosis for this condition is guarded. Cancerous tumors tend to be resilient, and treatment may not always yield the desired outcomes.
Recovery and Management
Ensure to schedule follow-up appointments every three months for your veterinarian to monitor for any new or ongoing growth or metastasis.