A 39-year-old female rhinoceros (Rhinoceros unicornis) had several vertical cracks and apical horn degeneration. The horn was removed with behavioral conditioning and gigli wire 1 cm above the germinal bed. Despite removal there was evidence of keratin damage below the removal site. This damaged area and a secondary area at the germinal bed, subsequently ruptured purulent material approximately 3 months later. The entire horn was then surgically amputated at the germinal bed. Healthy horn re-growth occurred in approximately 85% of the horn. There was an area that was dysplastic that cultures and biopsies identified yeast and bacterial agents. Several subsequent partial horn amputations failed to restore complete healing. A follow-up biopsy diagnosed the non-healing area to have transformed into squamous cell carcinoma. Serial radiographs and bone biopsies indicated a mild periosteal reaction present in the underlying bone. Partial horn amputation was performed again, but recurrence of squamous cell carcinoma occurred in another location. To obtain a cure portable radiation technology, developed by Xoft, inc. makers of Axxent® Electronic Brachytherapy, eBx™, System was elected. XOFT performed Electronic Brachytherapy in two doses spaced 7 days apart. Treatment with eBx™ utilizes a miniaturized x-ray source to deliver high dose radiation to a target area at low energy, hence it can be performed without a lead shielded room. The area of focused radiation has healed with scar tissue, and keratinaceous horn re-growth has only occurred in parts of the horn where radiation was not performed. She appears to be free of squamous cell carcinoma 1 year later. Squamous cell carcinoma has been previously reported in captive rhino.1-3
The primary author would like to thank the generous donation of time and equipment by UCLA and Xoft, Inc.
1. Naik SN, Ishwad CS, Karawale MS, Wani MV. Squamous cell carcinoma in an Indian rhinoceros. Vet Rec. 1986;118:590–591.
2. Nandi SN, Deb SK. Horn cancer in rhinoceros. Indian Vet J. 1972;49(9):881–882.
3. Goodman G, Rhind S, Meredith A. Successful treatment of a squamous cell carcinoma in a white rhinoceros, Ceratotherium simum. Vet Dermatol. 2007;18(6):460–463.