Breast Pathology Lecture Notes

Question-and-Answer flashcards covering embryology, anatomy, inflammatory disorders, benign tumors, carcinomas, prognostic factors, and hereditary/male breast cancer from the provided lecture notes.

Along what embryologic line can ectopic breast tissue or supernumerary nipples appear?

Anywhere along the milk line, which runs from the axilla to the vulva.

What is the functional unit of the breast responsible for milk production?

The terminal duct lobular unit (TDLU).

Which breast epithelial layer produces milk?

The inner luminal cell layer.

Which breast epithelial layer has contractile function to propel milk?

The outer myoepithelial cell layer.

Which hormones drive breast development after menarche?

Estrogen and progesterone.

In which quadrant is breast tissue densest?

The upper outer quadrant.

What is galactorrhea and is it a symptom of breast cancer?

Milk production outside of lactation; it is NOT a symptom of breast cancer.

Name two pathologic causes of galactorrhea.

Prolactinoma of the anterior pituitary and certain drugs.

What bacterium most commonly causes acute mastitis?

Staphylococcus aureus.

How is acute mastitis treated?

Continued drainage (breast-feeding) and antibiotics such as dicloxacillin.

Periductal mastitis is most commonly seen in what patient population?

Smokers.

What vitamin deficiency underlies periductal mastitis?

Relative vitamin A deficiency causing squamous metaplasia of lactiferous ducts.

How does mammary duct ectasia usually present?

As a periareolar mass with green-brown nipple discharge in multiparous postmenopausal women.

What mammographic finding often brings fat necrosis to clinical attention?

Abnormal calcification due to saponification.

What is the most common breast change in premenopausal women?

Fibrocystic change producing a lumpy breast, usually in the upper outer quadrant.

Which fibrocystic changes carry NO increased risk for invasive carcinoma?

Simple fibrosis, cysts, and apocrine metaplasia.

How much does atypical hyperplasia increase carcinoma risk?

Approximately 5-fold in either breast.

What benign lesion presents with bloody nipple discharge in a premenopausal woman?

Intraductal papilloma.

Which cell layer is absent in papillary carcinoma but present in intraductal papilloma?

The myoepithelial cell layer.

What is the most common benign breast neoplasm?

Fibroadenoma.

How does a fibroadenoma typically feel on exam?

Well-circumscribed, mobile, marble-like mass.

Which breast tumor shows leaf-like projections on biopsy and may be malignant?

Phyllodes tumor.

List three major risk factors related to estrogen exposure for breast cancer.

Early menarche/late menopause, obesity, and nulliparity (or late first pregnancy).

How is ductal carcinoma in situ (DCIS) usually detected?

As calcifications on mammography without a palpable mass.

What is Paget disease of the breast?

DCIS that extends to involve nipple skin, causing ulceration and erythema.

What clinical signs may indicate advanced invasive ductal carcinoma?

Skin dimpling or nipple retraction.

Which subtype of invasive ductal carcinoma has tumor cells floating in mucin pools?

Mucinous (colloid) carcinoma.

Which invasive carcinoma subtype is increased in BRCA1 mutation carriers?

Medullary carcinoma.

Which aggressive breast cancer mimics acute mastitis and blocks dermal lymphatics?

Inflammatory carcinoma.

What protein loss characterizes LCIS and invasive lobular carcinoma?

E-cadherin.

Preferred management for LCIS discovered on biopsy?

Tamoxifen and close follow-up (due to low but present invasion risk).

Most useful single prognostic factor before metastasis in breast cancer staging?

Status of axillary lymph-node involvement (assessed by sentinel node biopsy).

Which receptors predict response to anti-estrogen therapy like tamoxifen?

Estrogen receptor (ER) and progesterone receptor (PR).

Which targeted drug treats HER2/neu-positive breast cancer?

Trastuzumab (Herceptin).

'Triple-negative' tumors lack which three markers and have what prognosis?

They lack ER, PR, and HER2/neu and have a poor prognosis.

Mutation in which gene is linked to breast and ovarian cancers in women?

BRCA1.

Male breast cancer is most often of which histologic subtype?

Invasive ductal carcinoma.

Name two conditions associated with increased male breast cancer risk.

BRCA2 mutation and Klinefelter syndrome.