+ 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
  • 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%