Successful surgical removal of a pheochromocytoma in a mare via trans‐costal approach

Abstract

BackgroundPheochromocytomas have been previously reported in horses, but successful antemortem diagnosis and surgical removal without recurrence of clinical signs have not been described.ObjectiveTo report the clinical presentation, diagnostic evaluation, surgical technique, anaesthetic management and post‐operative care of a mare diagnosed with pheochromocytoma.Study designClinical case report.MethodsAn 18‐year‐old Quarter Horse mare presented for recurrent episodes of colic, profuse sweating, muscle fasciculations and agitation over a 2‐month period. Clinical, clinicopathologic and ultrasonographic (transcutaneous, transrectal) abnormalities were consistent with a unilateral left‐sided adrenal mass. Surgical removal of the mass was performed via a trans‐costal approach with removal of the 18th rib and retraction of the left kidney to improve exposure. Associated vasculature was ligated, and the adrenal mass was removed and submitted for histopathology and immunohistochemistry.ResultsA trans‐costal surgical approach provided excellent visualisation of the adrenal mass and allowed for identification and ligation of associated vessels. Total surgical and anaesthesia time were 86 and 114 min, respectively. Several intraoperative (hypertension, tachycardia) and post‐operative (colic with tachycardia, tachypnea, large colon pelvic flexure impaction and nasogastric reflux) complications were encountered and managed successfully. Immunohistochemistry demonstrated positive labelling for synaptophysin and chromogranin A, confirming diagnosis of pheochromocytoma. The mare had recovered well at 6‐week recheck post‐operatively and returned to training at 6 months post‐operatively. No further clinical signs consistent with pheochromocytoma have been observed following removal.ConclusionsThe trans‐costal approach allowed for surgical removal of a pheochromocytoma in a mare. Surgical removal of adrenal masses in horses may be associated with complications yet was successfully performed without subsequent recurrence of clinical signs associated with tumour presence and return to athletic use in this mare.

A pyramid needs a foundation: Exploding some myths about what EVJ's editors are looking for from authors?

“…In EVJ, case reports serve exactly these purposes; in our last three volumes, we have included case reports which documented new diseases such as a novel strain of Taylorella asingenitalis, 62 the first reported case of fragile foal syndrome type 1 in a Thoroughbred 63 and previously unknown sites of injury such as a site of subchondral bone injury in the calcaneus. 64 Case reports have been used to describe genetic markers in equine diseases 63,65 and highlight new approaches to treatment and diagnosis of rare conditions where it is unlikely to be feasible to assemble large case series such as surgical removal of pheochromocytoma, 66 transluminal angioplasty for jugular vein stenosis, 67 GnRH immunisation for granulosa theca cell tumour 68 and diagnostic approaches for ovarian conditions. 69 Case reports can be used to introduce new technology which is likely to be of interest to other clinicians, 70 and they are particularly appropriate for communicating adverse events where the authors are seeking to share the benefit of their experience in the hope that it will be helpful to others unfortunate enough to encounter the same challenge.…”