+ General Considerations
- Penile tumors account for 0.24% of all tumors in male dogs
- SCC and transmissible venereal tumor most common are the most common tumors of the penis and prepuce
- Other types include MCT, LSA, FSA, histiocytic reticulocytoma, TCC, CSA, fibroma, and papilloma
- LSA has been reported in association with penile prolapse in 1 dog
- OSA, osteoma, and multilobular osteochondrosarcoma have been reported in the os penis
- Leishmaniasis can cause nodular penile mucosal lesions
- Penile tumors usually occur in older dogs
- Transmissible venereal tumors occurs in 4-5-year-old dogs with increased risk in free roaming dogs
- Transmissible venereal tumors are transmitted by contact with genital mucous membranes during coitus
- Transmissible venereal tumors appear as multiple tumors along the penis and mucosal lining of the prepuce
+ Clinical Signs
- Preputial enlargement with frequent licking of the penis and prepuce
- Stranguria, dysuria, and hematuria
- Serosanguineous or hemorrhagic preputial discharge as most tumors are friable and bleed easily
- Painful
- ± urethral obstruction
+ Diagnosis
- Physical examination
- Cytology from FNA or impression smear
- Histopathology from incisional or excisional biopsy
+ Treatment
- Partial penile amputation
- Total penile amputation with scrotal urethrostomy ± penile urethrostomy if tumor extends into the proximal urethra
- Ventral midline preputiotomy for penile tumors that are large enough to allow penile extrusion through the preputial orifice (preputial splitting)
- Local tumor recurrence rate is high for dogs with transmissible venereal tumor and surgery is not recommended
- Transmissible venereal tumors are very response to chemotherapy and radiation therapy
- Chemotherapy: vincristine 0.5-0.7 mg/m 2 IV 4-8 times ± doxorubicin