Cystic disease of breast fibrocystic disease of the breast. cystic fibrosis a hereditary disorder related to widespread dysfunction of the exocrine glands, with an accumulation of excessively thick and tenacious mucus and abnormal secretion of sweat and saliva; it is inherited as a recessive trait; both parents must be carriers. The cause is assumed to be absence, insufficiency, or abnormality of some essential hormone or enzyme. Called also CF of the pancreas and mucoviscidosis. Effects. The symptoms and severity vary widely. Although CF is congenital, it's going to not happen significantly during the first weeks or months of life, or it's going to cause ileus and perforation within the newborn. The chief explanation for complications is that the extremely thick mucus produced. Normal mucus bathes and protects internal surfaces, transports chemicals produced in one organ through intricate small ducts to a different organ, and carries bacteria, dirt, and wastes to be eliminated from the body;