Dear Dr. Jorden: My dog is 9 years old and has started getting hard, marble-sized lumps under the skin. Some have ruptured. My vet says they are sebaceous cyst. Why have they suddenly started growing ...

A lipoma is a benign (noncancerous) tumor of fat in middle-aged or older dogs. Lipomas can grow anywhere on the dog's body, even inside their abdomen. But the most common growth is under their skin ...