Terminal ductal lobular unit

Each breast lobe is drained by a collecting duct terminating in the nipple. The collecting duct has several branches, which end in a terminal ductal-lobular unit (TDLU), the basic functional and histopathological unit of the breast. The TDLU is composed of a small segment of terminal duct and a cluster of ductules, which are the effective secretory units. The functional structures are surrounded by specialised connective tissue. A normal terminal ductal-lobular unit ranges from 1-4 mm.

The TDLU consists of the:

  • extralobular terminal duct 
  • intralobular terminal duct 
  • lobule (functional unit of the breast)

Function

This is the most important structure in the breast. It is the glandular unit that produces milk.

Related pathology

It is postulated that most cancers and benign lesions arise in the terminal duct either inside or just proximal to the lobule. For example:

Thoracic anatomy
Share article

Article information

rID: 15228
System: Breast
Section: Anatomy
Tag: cases
Synonyms or Alternate Spellings:
  • Terminal ductal lobular unit (TDLU)
  • TDLU
  • Terminal ductal and lobular units (TDLU's)
  • Terminal ductal and lobular unit (TDLU)

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.