Topic Overview

Clinical Anatomy of the Breast

Carcinoma of the Breast

• Most important pathology.

• Commonest site → upper outer quadrant (contains most glandular tissue, axillary tail).

• Spread pathways:

  • Local infiltration → into skin, nipple, pectoral muscles, chest wall.

  • Lymphatic spread → mainly to axillary nodes; also to parasternal, intercostal, subdiaphragmatic nodes.

  • Venous spread → through intercostal veins into vertebral venous plexus → vertebral metastasis.

• Clinical signs:

  • Skin dimpling → retraction of suspensory ligaments.

  • Peau d’orange (orange-peel skin) → due to lymphatic obstruction.

  • Nipple retraction → fibrosis around lactiferous ducts.

  • Fixed mass → infiltration of retromammary space, loss of mobility.

  • Contralateral breast spread → via parasternal lymphatics.

Benign Conditions

• Fibroadenoma → common benign tumor in young women.

• Fibrocystic disease → cyclical pain and nodularity.

• Intraductal papilloma → may cause bloody nipple discharge.

Infections

• Acute mastitis → infection in lactating women, often due to Staphylococcus aureus.

• May lead to breast abscess, especially in retromammary space.

Congenital Anomalies

• Polythelia → accessory nipple along embryonic milk line.

• Polymastia → accessory breast tissue, may develop anywhere along milk line (axilla common).

• Amastia → absence of breast.

• Gynecomastia → enlargement of male breast due to hormonal imbalance (seen in liver disease, puberty, drug-induced).

Surgical Importance

• Modified radical mastectomy → requires knowledge of lymphatic drainage for axillary clearance.

• Breast implants → usually placed in retromammary space or beneath pectoralis major.

• Sentinel lymph node biopsy → identifies first draining node; if free of disease, axillary dissection may be avoided.