+ 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