Fig. 9. Combination therapy is often helpful. Normally this would involve surgical removal (laser or sharp) with some form of chemotherapy or even radiation. A, This 6-year-old cremello horse was presented with a slowly expanding darkly pigmented tumor on its tail. Biopsy confirmed a highly malignant melanosarcoma. B, It was removed by wide laser surgical excision. C, A series of cisplatin beadsb
were inserted at 1-cm intervals around the margin prior to wound closure. D, The site was dressed using a tie-over
stent to support the wound. The site healed well and the horse showed no local recurrence. However, 4 years later the horse presented with thoracic and abdominal melanoma. No other skin lesions were identified. The reasonable assumption was that the dissemination arose from the cutaneous mass that had not been removed quickly enough.
is probably little point in continuing. If, however, there is a response then the treatment should con- tinue until 3 weeks after there is no further improvement.
Cisplatin
The value of cisplatin is also uncertain but the au- thor has had considerable success with treatment of melanomas using a cisplatin/sesame oil emulsion containing 1 mg/mL cisplatin. The material can be infiltrated into the lesion at 2-week intervals. There is no specific experience of its use on eyelid
melanoma. The emulsion appears to have no harmful or painful effects.10 Cisplatin combined with electro-permeabilization of the cells of the tu- mor (electrochemotherapy) could also be attempted. Slow release bio-degradable beads containing cispla- tin are also useful in some cases either solely or as an adjunctive measure to surgery (Fig. 9).
Mitomycin C
Mitomycin C does appear to have a specific anti- melanocytic effect and it can be a logical approach to
