Clinical features, outcome and prognostic factors in dogs diagnosed with non-cortisol-secreting adrenal tumours without adrenalectomy: 20 cases (1994-2009).

The aims of this study were to describe the clinical features, the outcome and the prognostic factors of dogs with non-cortisol-secreting adrenal masses without adrenalectomy, and also to provide clinical data that can be useful for making decisions when managing dogs with these types of neoplasms. Medical records from 1994 to 2009 were reviewed and 20 dogs were included in the study. The results showed that mean age at diagnosis for dogs with non-cortisol-secreting adrenal masses was 12 years with no sex predisposition. Most dogs were asymptomatic. The most frequent clinical signs, when present, were lethargy, weakness and hypertension. Radiological evidence of metastases at diagnosis was not frequent. The maximal dorso-ventral thickness of the adrenal mass ranged from 10.0 to 45.0 mm. Right adrenal gland masses were more frequent than left-sided. Hypertension was found to be related to tumour growth during follow-up. The median survival time of dogs with non-cortisol-secreting tumours was 17.8 months. Body weight at diagnosis, tumour size and the presence of metastases at diagnosis were inversely related to survival. In conclusion, survival of dogs with non-cortisol-secreting adrenal tumours without adrenalectomy is relatively high and comparable with that of dogs treated with adrenalectomy. Dogs with metastasis and large adrenal tumours have a poorer prognosis. Hypertension is related to tumour growth, and might be used as an additional tool to assess the potential growing capacity of the tumour.