Clinical features and relationship between treatment and prognosis were evaluated in 22 canine insulinomas. Nineteen dogs were middle or small-sized dogs weighing less than 20 kg, indicating a different tendency compared to several reports that large-breed dogs were commonly affected. Metastases were observed in 11 (69%) of 16 dogs surgically treated and the metastatic rate was higher than the past reports. One-year survival rate (56%) in dogs treated surgically was compatible with several reports and there is no difference of the survival interval compared to dogs treated medically alone. However, disease-free interval was significantly longer than that of dogs treated medically alone (P=0.0099). The clinical signs recurred within 3 months in 5 of 6 dogs treated medically alone. In addition, the result of the side effects by steroid and diazoxide may support a view that a medical treatment alone was not expected to a good quality of life. In conclusion, surgical treatment aimed at reducing tumor mass volume is useful for canine insulinoma unless there are diffuse metastases to the other organs.

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A seven-year-old male miniature Dachshund with left subauricular mass was treated surgically. The dog had an atresia of the external acoustic meatus and the mass was diagnosed as the accumulation of ear wax associated with hyperkeratosis.

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