Pheochromocytoma in Dogs

A pheochromocytoma is a tumour that develops in specialised tissue inside the adrenal gland—a small organ that sits near the kidney and produces hormones involved in stress response and blood pressure regulation. These tumours can release surges of adrenaline and related hormones into the bloodstream, sometimes unpredictably, which may create episodes of rapid heart rate, restlessness, heavy breathing, or collapse. In other cases, the release is steadier and signs develop more gradually. Owners often arrive at this possibility after observing intermittent episodes that seem out of character—panting without obvious cause, sudden weakness, or behaviour that suggests anxiety or discomfort—sometimes with normal periods in between. The episodes can vary in intensity and frequency, and in some dogs the condition is discovered incidentally during imaging or investigation for another concern. This page explores the signs that may prompt consideration of a pheochromocytoma, what is happening inside the adrenal gland and the wider body, how the condition is investigated through blood tests and imaging, and the approaches that exist for managing it, including surgery and medical options. The course and outcome depend on factors including the size and behaviour of the tumour, whether it has spread, and the individual dog's response to treatment.