Hypercortisolism and diabetes mellitus secondary to a steroid cell tumor of the ovary in a bat-eared fox (Otocyon megalotis)

reports in dogs 10 and cats 12 describe likely endocrinopathies based on physical examination and history, but without complete laboratory assessments. This report presents clinical and pathological data from a case of a steroid cell tumor in the ovary of a bat-eared fox (Otocyon megalotis) with hypercortisolism and diabetes mellitus. An 11-year-old nulliparous bat-eared fox was presented with bilateral protrusion of the nictitating membranes. The fox was obese and dehydrated and had a grade II/V systolic murmur. Abnormalities in serum biochemical parameters included elevations in blood urea nitrogen, glucose, alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, amylase, and cholesterol when compared to values obtained for this animal prior to the onset of signs (Table 1). Serum total bile acids (3.7 mmol/liter) were within reference ranges for fasting and postprandial concentrations in dogs. 1 Serum total thyroxine (2.3 mg/dl) concentrations were within the reference range for dogs. 3 Liver biopsies collected via laparotomy revealed moderate, diffuse hepatocellular hydropic degeneration suggestive of a steroid hepatopathy. The laparotomy site dehisced and became infected. The wound was managed with parenteral antibiotics, cleaning, and debridement. A low-dose dexamethasone test was performed after surgical dehiscence was nearly completely healed to evaluate the pituitary-adrenocortical axis. The baseline serum cortisol concentration was 2.8 mg/dl. Dexamethasone sodium phosphate (0.01 mg/kg) was administered intravenously. Serum cortisol concentrations were 2.4 mg/dl and 3.0 mg/dl 4 and 8 hours after dexamethasone administration, respectively. The adrenocorticotropic hormone (ACTH) concentration, assayed by radioimmunoassay, a was below detectable concentration, compared with 6.5 pmol/liter in a clinically normal conspecific. These findings were compatible with a diagnosis of a functional cortisol-secreting tumor. The blood glucose concentrations were variable, ranging from 65 to 195 mg/dl, until a marked hyperglycemia (350 mg/dl) was noted 3 months after the onset of signs. Glycosuria was also persistently present (. 100 mg/dl). Insulin