Outcome in dogs undergoing adrenalectomy for small adrenal gland tumours without vascular invasion

Veterinary studies have reported the outcome of adrenalectomies in dogs; however, these studies typically include a wide variety of adrenal tumour sizes, including cases with or without vascular invasion. The purpose of this study was to report outcome in a cohort of dogs with histologically confirmed small adrenal tumours without vascular invasion treated with adrenalectomy. This retrospective study was conducted using data from the University of Florida and University of California-Davis databases between 2010 and 2017. Dogs were included if they underwent excision of an adrenal gland tumour with a maximal diameter <= 3 cm, without evidence of vascular invasion to any location as assessed via computed tomography. Fifty-one dogs met the inclusion criteria. The short-term survival rate of dogs undergoing adrenalectomy was 92.2%, and one-year disease-specific survival was 83.3%. Twenty-eight of 51 (54.9%) dogs were diagnosed with a malignancy. Minor complications were observed commonly intra-operatively and post-operatively. Major complications were observed in six dogs, and included sudden death, respiratory arrest, acute kidney injury, haemorrhage, hypotension and aspiration pneumonia. Short-term mortality occurred in four dogs. Sudden death and haemorrhage were the most common major complications leading to death. While adrenalectomy is sometimes controversial because of the high perioperative mortality rates previously reported, the results of this study support that adrenalectomy for small tumours with no vascular invasion can be performed with low risk.