Mammogram type D is an extremely dense breast, consisting almost entirely of glands with dense breast tissue. Breast density grading is often used in mammography to report the density of the breast on mammography. Breast tissue density is categorized as A, B, C, or D according to the BI-RADS scale: Grade A: Almost entirely fat-based with few glands. Grade B: predominantly fatty with areas of dense fibrous glands present in small amounts. Grade C: Unevenly dense, predominantly glandular with some fat present. This type of breast may have small masses that are not easily detected by molybdenum. Grade D: Extremely dense, composed almost entirely of glands. Mammogram classification is an initial assessment of the breast and does not indicate a disease state. It is recommended that patients with abnormal mammogram results seek prompt medical attention to identify the cause and avoid delay.