ductular

Ductular is an adjective used in anatomy and pathology to describe structures related to ducts, especially small ducts known as ductules. The word derives from ductulus, the diminutive form of ductus, and is commonly used in histology to characterize features of the microduct system and its lining epithelium.

In histology and pathology, the term ductular often appears in reference to the ductular reaction, a proliferative process involving small duct-like structures near portal tracts in the liver. This reaction is thought to involve biliary-type epithelial cells and hepatic progenitor cells and is observed in various chronic liver diseases, cholestasis, and cirrhosis. Immunohistochemical staining frequently highlights cytokeratins such as CK7 and CK19 in ductular-type cells.

Ductular descriptions are also applicable beyond the liver. Small ducts and ductules occur in the pancreas, salivary glands, and other exocrine organs, where the ductular epithelium lines the luminal surface. In medical reporting, the term helps distinguish lesions and tissue architecture arising from ducts or ductules from those of acinar, glandular, or vascular structures.

Overall, ductular conveys relation to small duct systems and their epithelial lining, with particular emphasis in clinical pathology on the appearance and proliferation of ductule-derived structures in diseased tissue. It is most often encountered in discussions of biliary biology, liver pathology, and microanatomy of exocrine glands. See also duct, ductule, and biliary epithelium for related concepts.