+ Signalment
- Mean age 7 years for benign tumors and 11 years for malignant tumors
- No sex predilection
- Benign aural tumors: inflammatory polyp, papilloma, basal cell tumor, and ceruminous gland adenoma
- Ceruminous gland cysts are tumor-like lesions in cats which appear as sessile, blue-black masses
- Malignant aural tumors: ceruminous gland ADC, SCC, and other cutaneous tumors
- Ceruminous gland ADC is more common than ceruminous gland adenoma
- Malignant tumors tend to be locally invasive with a low metastatic potential (15% to regional lymph node and lungs)
+ Clinical Signs
- Mass
- Aural discharge, odour, pruritis, and local pain
- Neurologic signs in 10% of dogs with malignant aural tumors
- Duration of clinical signs prior to presentation is usually prolonged (months to years)
- Benign tumors are usually raised and pedunculated with rare ulceration
- Malignant tumors usually have a broad base with ulceration and hemorrhage
- 25% of malignant tumors have bulla involvement
+ Diagnosis
- Otoscope
- Survey radiographs
- CT
+ Treatment
- Surgical resection
- TECA-LBO for malignant tumors
- Lateral or vertical ear wall resection for benign tumors
- Caudal auricular approach described for cholesteotoma
- Radiation therapy as either primary or adjunctive treatment
+ Prognosis
- MST 11.7-50.3 months, but majority of cats die for reasons unrelated to aural tumor
- Malignant aural tumors are more aggressive in cats than dogs
- Poor prognostic factors include neurologic signs, histopathology of SCC or undifferentiated carcinoma, lymphatic or vascular invasion, and conservative surgery
- MST significantly worse for cats with neurologic signs (1.5 months v 15.5 months)
- MST significantly better for cats with ceruminous gland ADC (49 months v 3.8 months for SCC and 5.7 months for undifferentiated carcinoma)
- MST is significantly worse for tumors with lymphatic or vascular invasion (4.0 months v 21.7 months)
- Local tumor recurrence rate (25% v 66%), median DFI (42 months v 10 months), and 12-month survival rate (75% v 33%)
- Mitotic index of < 3 surviving significantly longer than cats with a mitotic index ≥ 3
- Radiation therapy (48 Gy total dose): median DFI 40 months and 12-month survival rate 56%