Cisplatin Intralesional Chemotherapy of Recurrence Schwannoma in Horse: A Case Report

Abstract

A 7-year-old crossbred stallion had multiple solitary cutaneous masses at the right infraorbital area which were recurrent for two months. The biggest mass size was 5 x 7 x 1 cm3 and had superficial bleeding. This case was diagnosed as peripheral nerve sheath tumors based on cytological and histological examination which showed numerous spindle cells with cancerous characteristics, cell patterns of the tumor were interlacing bundle and a whirl. Most areas showed tense palisading nuclei of tumor cells (Verocay bodies) known as Antoni A area. The rest showed loose paucicellular tissue known as Antoni B area. Within histologic sections, the cells showed positive immunoreactivity for S100 and calretinin, whereas immunoreactivity was not detected for CD34. Rapidly recurrent tumor was found after excision combined with cryotherapy. Consequent treatment using cisplatin (1mg/cm3) in autologous serum was intralesionally injected twice, 2 weeks apart. After the two injections, the horse responded with effective wound healing two months later. Therefore, intra-lesional injection of cisplatin should be considered for recurrent dermal Schwannoma or inadequate surgical removal of tumor.