Partial Phallectomy for the Treatment of Penile Squamous Cell Carcinoma in a 25-Year-Old Gelding

Abstract

Squamous cell carcinoma (SCC) is the most common neoplasm affecting the external genitalia of male horses, in particular aged geldings. This case report describes the surgical management of a large SCC of the glans penis of a 25-year-old gelding using the Williams partial phallectomy technique. The gelding presented with a swollen prepuce with foul-smelling discharge and abnormal micturition. Physical examination revealed an ulcerative mass eroding the glans penis, and cytology indicated squamous epithelial dysplasia with septic neutrophilic inflammation. Based on the lesion’s characteristic cauliflower-like appearance and cytological findings, SCC was suspected and surgical excision was decided. Partial phallectomy according to Williams was performed, selected for its indication for masses invading the tunica albuginea whilst allowing for shorter anaesthesia time due to the gelding’s advanced age. Palpation and ultrasonography of inguinal lymph nodes were unremarkable and lymph node resection was not included in the treatment plan. Postoperative histopathological examination indicated a well-differentiated SCC with vascular and lymphatic invasion though. The horse recovered well with no complications and normal urination one month after surgery. However, three months post-operatively, recurrence was suspected due to preputial sheath enlargement and abnormal ultrasonographic findings, indicative of a metastatic process. This report highlights the challenges associated with the management of equine penile SCC, particularly in aged horses, and the importance of early detection. Williams partial phallectomy proved to be practical and effective, offering a satisfactory short-term outcome. However, the risk of recurrence remains a significant concern and owners need to be aware of the guarded prognosis.