Signalment

•mean age 9 years for benign tumors and 10 years for malignant tumors

•no sex predisposition ± male

•breed predisposition: Cocker Spaniel (possible association with propensity for otitis externa) and Boxers

•inflammation is a precursor to tumor development with increased glandular dysplasia

•benign aural tumors: inflammatory polyp, papilloma, basal cell tumor, and ceruminous gland adenoma

•malignant aural tumors: ceruminous gland ADC, SCC, and other cutaneous tumors

•malignant tumors tend to be locally invasive with a low metastatic potential (10% 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, and 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

•malignant aural tumors are less aggressive in dogs than cats

•poor prognostic factors include bulla invasion, extensive tumor involvement, and conservative surgery

•survival time significantly better for ceruminous gland ADC compared to SCC

•MST significantly better for tumors without extensive involvement (> 58 months v 5.3 months)

•MST (36 months v 9 months) and local tumor recurrence rate (0% v 75%) are significantly better for tumors treated with TECA-LBO compared to lateral ear wall resection

•radiation therapy (48 Gy total dose): median DFI 40 months and 12-month survival rate 56%