CONDITION
Adrenal Tumours
Adrenal tumours are growths that develop in one or both of the small adrenal glands, which sit just above the kidneys and produce hormones that help regulate metabolism, blood pressure, and the body's response to stress. These tumours can be benign or malignant, and some produce excess hormones while others remain silent and are discovered incidentally during imaging for other reasons. Owners may notice changes that develop gradually over weeks to months—increased thirst and urination, a pot-bellied appearance, muscle weakness, or changes in coat quality. In other cases, a tumour may be found on an ultrasound or CT scan performed for an unrelated concern, with no outward signs at all. The pattern of signs often depends on which hormones, if any, the tumour is producing, and whether it is growing in a way that affects surrounding structures. This page explores what signs may appear and why, what is happening inside the adrenal gland, how these tumours are identified and characterised, and the range of approaches that exist for managing them. Each case tends to be individual, shaped by the type of tumour, the hormones involved, and the overall picture of the animal's health.
Why this matters now
Adrenal tumours tend to appear in middle-aged to older dogs and cats, most often between eight and eleven years of age, though they can develop at any point in adult life. Certain breeds, including Poodles, Dachshunds, and Terriers, appear in clinical records more frequently, though the reasons for this are not fully understood. In many cases, the tumour has been present and growing quietly for months or years before any outward change becomes noticeable.
The timeline of change varies widely depending on whether the tumour is producing hormones and how quickly it is growing. Some tumours remain small and silent for years, discovered only when imaging is performed for another reason. Others trigger a gradual accumulation of signs over weeks to months as hormone levels rise, or as the growing mass begins to press on nearby blood vessels or organs. Malignant tumours may eventually spread to the liver, lungs, or lymph nodes, though this progression can be slow and unpredictable.
Signals & patterns
Early signals
Increased thirst and urination
An owner may notice the water bowl being emptied more often, or the dog asking to go outside more frequently, particularly overnight. This pattern can develop gradually and may be mistaken for age-related change or a urinary infection.
Changes in appetite or weight
Some animals become noticeably hungrier, eating with more urgency or scavenging in ways they did not before. Others may lose weight despite eating normally, or gain weight in unusual patterns, particularly around the abdomen.
Coat thinning or slow regrowth
The fur may become sparse, dull, or slow to grow back after clipping. The skin underneath can feel thin or papery to the touch. These changes often appear symmetrically on both sides of the body.
Muscle weakness or fatigue
The animal may tire more easily on walks, struggle to jump onto furniture, or show less interest in play. Muscle loss can be subtle at first, most noticeable over the hind legs and along the spine.
Pot-bellied appearance
The abdomen may begin to sag or distend, giving a rounded profile even in animals that are not overweight. This develops over weeks to months and can be accompanied by thinning of the limbs.
Later signals
Panting or restlessness
The animal may pant heavily without exertion, particularly at night, and seem unable to settle. This can reflect changes in metabolism, muscle function, or the body's ability to regulate temperature and stress.
Skin bruising or fragility
The skin may bruise easily from minor contact, or develop thin areas that tear or bleed with little provocation. Wounds may heal more slowly than expected.
Collapse or weakness episodes
Some animals experience sudden episodes of weakness or collapse, particularly if the tumour has affected blood pressure, electrolyte balance, or blood flow to major organs. These episodes may resolve on their own but tend to recur.
Abdominal swelling or discomfort
As the tumour grows larger, it may cause visible swelling in the flank or a reluctance to lie in certain positions. In some cases, the mass can be felt through the body wall or detected as a firmness during gentle handling.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
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