Equine Penile and Preputial Tumours

Penile and preputial tumours are commonly encountered in elderly male horses and squamous cell carcinoma (SCC) is by far the most common type. reports on breed pre- dilection for penile tumour formation are equivocal but castration, coat colour, poor genital hygiene and infectious agents (EcpV-2) have been suggested to predispose to the development of SCC1. Careful assessment of the primary tumour is an important first step in the design of an optimal treatment protocol. tumour size, invasiveness, dif- ferentiation grade and presence of metastases are relevant to the decision to pursue additional diagnostic procedures or specific treatment options2.

Poorly differentiated SCCs on the external genitalia of the male horse seem to metasta- sise relatively frequently, but prospective research on the relationship between tumour grade, treatment performed and incidence of recurrence is needed to confirm this clini- cal impression. Because invasion of penile tumours into the corpus spongiosum, corpus cavernosum penis and urethra carry a higher risk of metastasis3,4, standard use of ultra- sonography to assess tumour extent (already a standard procedure in man) should be considered.

Complete elimination of the neoplasm and therefore risk of recurrence is highly dependent on the type of therapy chosen. treatment modalities, such as local excision and partial phallectomy (i.e. Williams’ technique), have a relatively high incidence of recurrence. More invasive therapies have a lower incidence of recurrence but post oper- ative complications are common and more serious. the introduction of a classification system for equine SCCs may aid the clinician in therapeutic decision-making and in the evaluation of the results of treatment2. Such a classification system may also further facilitate exchange of information between treatment centres, contribute to the devel- opment of therapeutic guidelines and help in prognostication.