Breast Tumors Overview

Tumors of the Female Breast

• Benign Epithelial Tumors:

  • Fibroadenoma: Characterized as focal lobular hyperplasia, not a true neoplasm. Involves both epithelial and connective tissues. Commonly arises in young women, presenting as a small (often less than 3 cm), firm, whitish, well-defined, highly mobile lump. It's often multiple and easily enucleated during surgery, though not truly encapsulated. Microscopically, a pericanalicular or intracanalicular pattern may be present. Fibroadenomas are entirely benign and do not tend to become malignant.

  • Duct Papilloma: Less common than fibroadenomas, typically appear in middle-aged women and are a common cause of bloody nipple discharge. Usually a single lesion arising within a large duct. Duct papillomas aren't premalignant but rarely multiple papillomas are associated with a greater risk of malignant change. Often less than 3 cm in size.

• Adenomas: Rarer than fibroadenomas and duct papillomas

  • Tubular Adenomas: Well-circumscribed, typically 10-40 mm in size, commonly found in women in their early twenties, most often in the upper outer quadrant of the breast. Composed of densely packed, uniform tubular structures with little stroma.
  • Lactating Adenomas: Originate as tubular adenomas, which undergo changes during pregnancy.

• Nipple Adenomas: Present as a subtle nodule under the nipple, usually less than 15 mm in diameter, affecting women of all ages. A haphazard arrangement of proliferating tubular structures composed of epithelial and myoepithelial cells, accompanied with significant fibrous stroma. The skin might appear ulcerated, and there may be blood-stained discharge. This can sometimes be mistaken for Paget's disease.

Malignant Epithelial Tumors of the Breast

• Mammary Carcinoma: The most frequent malignancy in women worldwide. Classified based on origin from the ducts or lobules:

  • A- Ductal Carcinomas:

    • Intraductal Carcinoma (in situ): A pre-invasive stage, where the abnormal cells are confined within the milk ducts. Usually are a small, hard mass that can cause bloody or serous nipple discharge, but no infiltration of the basement membrane. Good prognosis if the cells stay confined.

    • Infiltrating Duct Carcinoma (NOS): Most common, forming up to 75% of all breast cancers. Characterized by a hard mass with an ill-defined border, often in the upper outer quadrant. Often gives a gritty sensation during palpation due to significant fibrous stroma; the nipple can also retract. (Scirrhous).

    • Other specific types: Medullary, Tubular, Colloid (mucoid), Papillary

    • Medullary Carcinoma: Accounts for about 3% of invasive cancers, well-defined and soft, typically 10-40 mm in diameter. Often mixed with lymphocytes. Relatvely good prognosis.

    • Tubular Carcinoma: A rare form (about 2%) composed of small, regular epithelial cells with infrequent mitoses (nuclear division), diameter usually less than 1cm, and firm. Low-grade malignancy.

    • Mucoid (Colloid) Carcinoma: Rare (less than 1%), characterized by a well-defined gelatinous gross appearance, with small, regular malignant cells in clumps.

    • Papillary Carcinoma: Very rare (less than 1%), characterized with finger-like projections.

  • B- Lobular Carcinomas:

    • Lobular Carcinoma in Situ (LCIS): Less common than ductal carcinoma in situ. Often an incidental finding.
    • Infiltrating Lobular Carcinoma: Represents 10% of invasive cancers, composed of infiltrating small, rounded, regular epithelial cells with limited mitoses. This often follows strands or linear cords (Indian file) pattern, often multicentric and bilateral. Better prognosis than invasive duct carcinoma.

  • Paget's Disease of the Breast: Always associated with underlying ductal carcinoma in-situ. Involves the deeper layers of the epidermis, showing skin changes like itching, redness, and possible small ulcers around the nipple and areola.

Non-Epithelial Tumors

• Phyllodes Tumor (Giant Fibroadenoma): Uncommon, predominantly appearing after age 40, usually greater than 5 cm in diameter. Microscopically, the epithelial component has proliferating leaf-like structures. The stroma may be benign, mimicking fibroadenoma, or can display malignant features with significant mitotic activity and sarcomatous pattern.

Tumor Spread

• Direct Spread: To surrounding skin, deep fascia, pectoral muscles, ribs and pleura. May become highly fixed.
• Lymphatic Spread: Via axillary, internal mammary, mediastinal and supraclavicular lymph nodes, with potential to form small nodules under the skin.
• Blood Spread: To lungs, bones, brain, liver, and adrenals.

Risk Factors of Breast Cancer

• Age: Risk increases with age.
• Reproductive History: Longer interval between menarche and menopause, and older age at first full-term pregnancy are risk factors.
• Lifestyle: Obesity and high-fat diet.
• Genetics: Family history of breast cancer. Geographic and environmental factors.
• Previous Biopsies: Atypical hyperplasia in previous breast biopsy.
• Multiple Ductal Papillomas: Increased risk.