A 7-year-old intact male Golden Retriever presents with polyuria, polydipsia, and a pendulous abdomen. Bloodwork reveals mild hyperglycemia, elevated ALP, and hypokalemia. Urine cortisol:creatinine ratio is elevated. A low-dose dexamethasone suppression test fails to suppress cortisol at 8 hours. An ACTH stimulation test shows an exaggerated response. Abdominal ultrasound reveals bilateral adrenal enlargement. Which additional finding would most strongly suggest concurrent occult neoplasia rather than PDH alone?

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