A 14-year-old female spayed crossbred cat presented to the Animal Medical Center of Gifu University with clinical signs of a nasal discharge, epistaxis and mouth breathing. A computed tomography (CT) scan of the skull revealed a mass affecting the nasal cavities bilaterally, which extended into the right orbit and damaged the palatine bone and cribriform plate; there was extension into the olfactory bulb. A transnasal blind pinch biopsy of the mass was submitted for histopathology. The morphological features, phosphotungstic acid haematoxylin (PTAH) staining pattern and immunohistochemical findings (positivity for cytokeratin and the presence of mitochondria) were consistent with a diagnosis of oncocytoma (Head et al. 2003).
Treatment began with alternating doses of 15 mg/m2 doxorubicin (Adriacin; Kyowa Hakko Kirin) intravenously (iv) and 100 mg/m2 carboplatin (Paraplatin; Bristol-Myers Squibb) iv given every 3 weeks with concurrent radiation therapy and was well-tolerated. A total of 42Gy in 7 weekly fractions was prescribed using orthovoltage radiation.
A repeat CT scan was performed after 6 weeks and this showed tumour regression (Fig 1) with a significant reduction in the clinical signs, however the patient died suddenly 1 week later.
This is a rare tumour, however a combination of chemotherapy and radiotherapy appears to be a potential treatment option. The patient did not develop chemoradiotherapy-related toxicities, although the cause of sudden death in this case was not known.