Fibroglandular

Fibroglandular tissue refers to the portion of breast tissue that consists of fibrous connective tissue and glandular tissue (lobules and ducts). It is used to describe the non-fat component of the breast and is a common descriptor in radiology reports.

The fibroglandular component includes the stroma (supportive tissue) as well as ductal and lobular epithelium. Its amount varies with age, hormonal status, pregnancy, and menopause. Generally, younger women have a higher proportion of fibroglandular tissue, while aging and the postmenopausal state often lead to more adipose replacement and lower overall density.

On imaging, fibroglandular tissue appears radiodense on mammography. Higher density can mask underlying lesions and is commonly reported as breast density, which can be expressed as a percentage or using BI-RADS density categories. Dense breasts may require additional imaging and can influence screening strategies.

Clinical significance centers on breast density as a radiographic trait. A higher proportion of fibroglandular tissue is associated with an increased relative risk of breast cancer compared with predominantly fatty breasts, and density can affect the sensitivity of mammography. Density is influenced by genetics, hormones, body mass index, and age, and it is not a disease in itself but an anatomical characteristic with implications for screening and risk assessment.