Veterinary Society of
Surgical Oncology

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%

EXTERNAL EAR TUMORS

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