July 28, 2023
A duct is a small hollow tube lined by epithelial cells that connect together to form the walls of the tube. It acts like a pipe, connecting glands found deep inside tissue to the surface of the tissue or outside of the body. The purpose of a duct is to provide a path for fluids to move from one place to another.
Ducts are found throughout the body and the size of the duct depends on the amount of fluid being produced. Large caliber ducts can be found in the breast, liver, pancreas, and gallbladder while smaller caliber ducts can be found in the skin, salivary glands, and prostate gland.
Many different types of cancer start from cells normally found inside a duct including invasive ductal carcinoma of the breast, invasive ductal adenocarcinoma of the pancreas, and salivary duct carcinoma of the salivary glands.
In pathology, a duct is described as dilated if it is larger than normal. Ducts often become dilated if something (such as a tumour) is blocking one end of the duct which causes the duct behind the blockage to fill up with fluid and stretch.
In pathology, obstruction of a duct means that something is blocking the inside of the duct. For example, the duct leading from the parotid gland to the mouth can become obstructed by a stone or sialolith which can cause pain or swelling in the parotid gland.