CLINICAL COMMUNICATION KLINIESE MEDEDELING

Use of Ir¹⁹² interstitial brachytherapy for an equine malignant dermal schwannoma

M N Saulez^I; A Voigt^I; J C A Steyl^II; E van Wilpe^III; J Kotzen^IV; F Daniels^V

^ISection of Equine Medicine, Department of Companion Animal Clinical Studies
^IISection of Pathology, Department of Paraclinical Studies and
^IIISection of Anatomy, Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria Private Bag X04, Onderstepoort, 0110 South Africa
^IVDepartment of Radiation Oncology, University of Witwatersrand and Charlotte Maxeke Johannesburg Academic Hospital
^VDepartment of Radiation Oncology, Steve Biko Academic Hospital

ABSTRACT

A 10-year-old Hanoverian mare was evaluated for a right buccal swelling that recurred 3 months following surgical resection. Ultrasonographic examination showed a broadly pedunculated subcutaneous mass at the level of 106-109 and 406-409 cheek teeth associated with an erosive mucosal lesion on the inside of the cheek. Histological examination of a biopsy specimen revealed a well-demarcated, malignant, dermal schwannoma. Following subcutaneous placement of platinum coated Ir¹⁹² wires under general anaesthesia, low-dose radiation of 5 gray per day was delivered for 14 days. Short-term complications included loss of patency of the right nasolacrimal duct, erythema, dermatitis, leukotrichia and left-sided deviation of the muzzle. Ten months later, there has been no tumour recurrence. Findings suggest that the use of interstitial brachytherapy should be considered for a malignant, dermal schwannoma that has recurred or is not amenable to surgery.

Keywords: horse, implant, iridium-192, radiation therapy

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Received: August 2009
Accepted: November 2009

* A portion of this work was presented at the South African Society of Clinical and Radiation Oncology and the South African Society of Medical Oncology, Cape Town, 2009.
** Author for correspondence. E-mail: montague.saulez@up.ac.za