TL;DR: A growth on your dog's penis or prepuce requires a veterinary examination within 24–48 hours to identify if it is benign or malignant. Seek immediate emergency care if the growth is bleeding excessively, causing pain, or preventing urination.
What causes a growth or tumor on my dog's penis?
A growth or tumor on a dog's penis or prepuce (the sheath) can be several things. Only a veterinarian can determine the exact cause through specialized testing, which may include:
- Benign warts known as papillomas
- Inflammatory masses
- Transmissible Venereal Tumors (TVT)
- Mast cell tumors
- Squamous cell carcinomas
Is a growth on my dog's penis a veterinary emergency?
This situation is classified as Medium Urgency. While a growth is typically not an immediate life-threatening emergency, it requires a veterinary examination within 24 to 48 hours. Seek care more immediately if:
- The growth is bleeding excessively
- There is a visible blockage that prevents your dog from urinating
- Your dog seems in significant pain
How does providing a photo of the growth help with triage?
Providing a clear, high-resolution photo of the area is incredibly helpful for triage because it allows a professional to:
- Assess the growth's color, texture, and size relative to the surrounding tissue.
- Determine the speed at which you need to be seen by a veterinarian.
- Prepare for specific diagnostic steps, such as a fine needle aspirate or biopsy, before you even arrive.
Clinical Context (Merck Veterinary Manual)
Canine transmissible venereal tumors (TVTs) are a potential cause of growths on the penis, appearing as cauliflower-like, pedunculated, nodular, papillary, or multilobulated masses ranging from small nodules (5 mm) to large masses (>10 cm). These tumors are typically firm but friable, with a surface that is often ulcerated, inflamed, and bleeds easily. TVTs are almost always located on the genitalia and are transplanted through direct contact. Phimosis, or the inability to extrude the penis, can also be caused by neoplasia, among other etiologies. A physical examination of the prepuce and penis is essential for diagnosis.
Chapter: Oncology
Source: The Merck Veterinary Manual, 11th Edition (Page 1408)