TREATMENT OF A LARGE VULVAR SQUAMOUS CELL CARCINOMA BY RADICAL EXCISION AND INJECTABLE CISPLATIN

Introduction

A recently rescued 10-year-old paint mare was presented for treatment of a large perineal/vulvar mass. The current owner noted a 7.5 cm roundish mass growing from the left vulva 3 months prior to examination. Since the first observation, the mass enlarged from 7.5 cm to approximately 20 cm and became multilobulated.

Description of the Case

On presentation, the patient was profoundly anemic (PCV 11) with leukocytosis (WBC 15,500). Expecting significant blood loss at excision, antibiotic therapy and iron supplementation were initiated prior to surgery. After 7 days, PCV increased to 19 and WBC decreased to 9,900; but the tumor size grew approximately 25%. The mass had characteristics of a squamous cell carcinoma (SCC) and was excised followed by intralesional injection of cisplatin. In addition to the tumor, the exposed region contained maggots, abscesses and necrotic tissue. During the next 4 months, a total of 240 mg of cisplatin in sesame oil was injected (approximately 50 mg every 2-3 weeks). Histopathology confirmed SCC. With radical excision and cisplatin treatment, the owner's expectation of a comfortable and relatively normal outcome was realized. Discussion: SCC of the vulva is a common tumor in horses. It is treatable by the general practitioner, and the overall cost of medicines and procedures was not unreasonable for the average horse owner. Only 20% of SCC of the mucocutaneous junction are considered to metastasize which allows control of tumors with local therapy. Cisplatin is toxic and care must be taken to prevent exposure while mixing and administering the drug.

Conclusion

With radical excision and intralesional cisplatin, it was possible to reasonably control tumor growth and provide the patient with a favorable prognosis for life.