According to the inquiry of Health Insurance Network, there is a lump in the dog kidney, which may be caused by many reasons. There are several possible reasons:

1, acute renal failure: Acute renal failure is a sudden disease, which is extremely harmful to dogs. Dogs with acute renal failure can't live for days. Acute renal failure is often caused by poisoning, and preservatives, poisonous plants, rat poison and some prescription drugs are the common culprits.

2, chronic kidney disease: chronic kidney disease is sometimes called chronic renal failure, which is the result of renal function degradation. Chronic kidney disease is more common in elderly dogs.

3. Hypertension: As the dog gets older, it may have high blood pressure, which may lead to problems with its kidneys.

4. kidney calculi: kidney calculi is a common kidney problem in dogs, which may lead to a lump in the kidney.