EQUINE VETERINARY EDUCATION Equine vet. Educ. (2020) 32 (11) 565 doi: 10.1111/eve.13133_1


Case Report


Malignant glucagonoma associated with hyperglycaemia, hypertriglyceridaemia, Candidiasis and bacterial pneumonia in a 12-year-old Arabian gelding


R. E. Ruby†* , A. Fales-Williams‡, D. M. Wong† and B. A. Sponseller†


†Department of Veterinary Clinical Sciences, University of Kentucky, Lexington, Kentucky; and ‡Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA


*Corresponding author email: rebecca.ruby@uky.edu Keywords: horse; hyperglycaemia; endocrine neoplasia; glucagon; cachexia


Summary A 12-year-old Arabian gelding presented with a 10-day history of rapid, profound weight loss. Physical examination revealed tachycardia and tachypnoea. Body condition was 1/9 and characterised by severe muscle wasting. Other abnormal findings included multiple ulcerations on the tongue. A complete blood count revealed mild anaemia, neutrophilia and lymphopaenia. A blood chemistry panel showed mild electrolyte abnormalities, low albumin concentration, increased GGT activity and marked hyperglycaemia (15.16, RR 4.4–6.3 mmol/L). Triglycerides were markedly elevated (51.94 mmol/L, RR <0.57 mmol/L). Thoracic ultrasonography revealed scattered areas of


bilateral pleural thickening throughout the dorsal and cranioventral lung fields. Blood glucose was monitored every 4 h with a point-of-care glucometer and confirmed persistent hyperglycaemia ranging from 15.2 to 23.3 mmol/L. Plasma insulin levels were within normal limits (11.5 lIU, RR 2–25 lIU). Sixteen hours following presentation, the horse became acutely recumbent, unable to rise and had a heart rate of 100 beats/min and blood glucose of 23.3 mmol/L. Due to the


rapid decline in clinical signs, guarded prognosis, and financial constraints, humane euthanasia was elected. . Post-mortem examination revealed multifocal ulceration of


the oral cavity, oesophagus and stomach (Fig 1). Cytology of these areas showed large numbers of fungal hyphae. Within the lungs were small areas of multifocal abscesses with a larger, fluid filled space containing 300 mL of thick pink-tan


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Fig 2: Photomicrograph of the neoplastic cells within the liver. These cells form islands and nests, displacing normal hepatic architecture. Magnification 203.


fluid. Cytology of this fluid demonstrated suppurative inflammation, fungal hyphae and a mixed bacterial population of cocci and rods. Within all lobes of the liver, extending into the parenchyma, were multifocal tan areas. No abnormalities were found within the pancreas. Histopathologic evaluation of the liver masses showed a neoplastic cell population composed of cellular nests separated by bands of loose fibrous tissue (Fig 2). Immunohistochemical staining of the neoplastic cells within the liver had negative immunoreactivity for pancreatic polypeptide, insulin, and ACTH, but had positive immunoreactivity for chromogranin A and glucagon. This pattern of immunoreactivity confirmed the diagnosis of malignant glucagonoma within the liver. The areas of ulceration throughout oral cavity, oesophagus and stomach were confirmed as severe ulcerative and purulent oesophagitis and gastritis with mucosal hyperplasia and yeasts consistent with Candida albicans.


Key points


• Malignant glucagonoma is a rare neoplasm of the pancreas, or rarely the liver


Fig 1: Post-mortem appearance of the oral cavity showing multifocal areas of ulceration and surrounding epithelial hyperplasia. Histopathology of these sections showed ulceration and fungal overgrowth.


• Clinical manifestations may include hyperglycaemia, cachexia and secondary infections


• Diagnosis requires either ante-mortem levels of blood glucagon or post-mortem examination to confirm neoplastic cells with immunoreactivity for glucagon


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