The phrase "sac disease" refers to a medical condition that affects a specific part of the body called a sac. This condition may cause problems or abnormalities in the functioning of the sac, leading to health issues.
In some cases, the dog had an episode of diarrhea or digestive upset a week or two before the clinical signs of anal sac disease became evident. (glenerinanimalhospital.com)
«Obesity in Dogs,» «Anal Sac Disease in Dogs.» (pets.webmd.com)