Mammography: History and Anatomy Notes

History of Breast Cancer and Breast Imaging

  • Edwin Smith Papyrus (1862):

    • Earliest known record of breast cancer; ancient Egyptian medical text.

    • Oldest known surgical treatise on trauma.

  • Andreas Vesalius (1514–1564):

    • Advanced understanding of the breast.

    • Used ligatures instead of hot cautery for excising breast tumors, advised wide margins.

  • Henri François Le Dran (1757):

    • Recognized cancer could spread to axillary nodes.

    • Upheld axillary dissection as part of surgical treatment.

  • James Paget (1814-1899):

    • Researched Paget’s disease.

    • Common treatment: removal of breast and axillary lymph nodes.

Breast Anatomy

  • Mammary Gland vs. Breast:

    • Anatomy textbooks use "mammary gland."

    • Radiography textbooks use "breast."

    • Mammary gland: Lobulated glandular structure in the superficial fascia of the anterolateral thorax.

  • Divisions of Breast:

    • Quadrants: UOQ (most cancer cells develop). More glandular tissue.

    • Clock Positions: Used to localize lesions aside from divisions in relation to the nipple.

    • Regions:

      • Posterior: Closest to the chest wall.

      • Middle: Middle of the breast.

      • Anterior: Located behind the nipple.

      • Subareola: Behind the areola.

  • External Anatomy:

    • Nipples: 15-20 orifices, lactation, ejection.

    • Areola: Pigmented area around the nipple, contains Morgagni’s tubercles, lubricates nipple.

    • Montgomery’s Glands: Secrete oily substance, lubricate and moisturize, antimicrobial properties, pigmentation depends on estrogen level and age.

    • Morgagni’s Tubercles: Sebaceous glands that lubricate the nipple and areola.

    • Skin: Covers the breast, has sweat glands, thickest at the base.

    • Axillary Tail: Extension of tissue into the armpit, contains breast tissue and lymph nodes.

    • Inframammary Fold: Natural boundary of the breast.

  • Internal Anatomy:

    • Fascial Layers:

      • Superficial layer (anterior).

      • Deep layer (posterior).

    • Retromammary Fat Space: Between breast tissue and pectoralis muscle, common site of breast implant.

    • Pectoralis Muscles:

      • Major: Large, fan-shaped, covers upper chest.

      • Minor: Small, triangular, supports the breast.

    • Breast Parenchymal Components:

      • Fibrous Tissue: Holds/maintains position, predominates in older women.

      • Glandular Tissue: Predominates in younger women.

Male vs. Female Breast

  • Male Breast:

    • Rudimentary and without function.

    • Rarely subject to abnormalities.

  • Female Breast:

    • Secondary sex characteristics.

    • Accessory glands for milk production during lactation.

    • 15-20 lobes, divided into lobules containing glandular elements (acini).

    • Supported by Cooper's ligaments.

  • Stages of Breast Development:

    • Stage 1: Preteen, nipple raised.

    • Stage 2: Buds appear, breast and nipple raised, areola gets larger.

    • Stage 3: Breasts larger, glandular tissue present.

    • Stage 4: Areola and nipple form a second mound.

    • Stage 5: Mature adult breast, rounded, nipple raised.

  • Hormones:

    • Estrogen: Stimulates ductal tissue growth.

    • Progesterone: Prepares mammary glands for milk production.

    • Prolactin: Stimulates milk production.

    • Oxytocin: Ejects milk during breastfeeding.

  • Tissue Variations:

    • Younger women: Dense with glandular and fibrous tissue.

    • Older women (40+): Glandular tissue decreases, fat tissue increases.

    • Post-menopause: Mostly fat.

  • Breast Density: Refers to the amount of glandular and fibrous tissue compared to fatty tissue. Dense breasts appear white on mammograms.

    • Categories: Almost entirely fatty, Scattered areas of fibroglandular density, Heterogeneously dense, Extremely dense.

Histology of the Breast

  • Terminal Ductal Lobular Unit (TDLU):

    • Lined with epithelial and myoepithelial cells.

    • Produce milk during lactation.

    • Primary source of breast cancer precursors and cancers.

    • TDLUs involute (shrink) with age and after childbearing.

  • Terminal duct and glandular acinus:

    • Produce milk during lactation

  • Ampulla: reservoir of milk

  • Lactiferous duct: milk-carrying duct

  • Cellular Components:

    • Epithelial Cells: Form branching ductal system.

      • Become carcinomas when malignant.

      • Ductal Carcinoma in situ (DCIS): Cancer limited to the duct, pre-cancerous.

      • Invasive Intraductal Breast Cancer: Abnormal cells break through basement membrane.

    • Luminal Epithelial Cells: Produce milk, target for carcinogenesis.

    • Myoepithelial Cells: Contract to expel milk, form structural barrier.

    • Basement Membrane: Separates epithelium from stroma, prevents tumor spread.