Delve into breast pathology, covering developmental disorders and key clinical presentations. Learn about breast pain, nipple discharge, and palpable masses, di
BREAST PATHOLOGY --- DISORDERS OF DEVELOPMENT--- 1. MILK LINE REMNANTS Definition: The milk line is an ectodermal ridge extending from the axilla to the perineum. Failure of complete regression leads to supernumerary (extra) nipples or breast tissue along this line. Key Points: - Result from persistence of epidermal thickenings along the milk line - Most commonly come to attention due to painful swelling prior to menstruation - Disorders of normally situated breasts only very rarely arise in these heterotopic foci - --- 2. ACCESSORY AXILLARY BREAST TISSUE Definition: In some women, the normal ductal system extends into the subcutaneous tissue of the chest wall or axillary fossa — this extension is called the axillary tail of Spence . Key Point: - Because this tissue lies outside the breast proper, prophylactic mastectomy markedly reduces but does not completely eliminate the risk of breast cancer — this accessory tissue may be left behind - --- 3. CONGENITAL NIPPLE INVERSION Definition: Failure of the nipple to evert during development. Common and may be unilateral. Key Points: - Usually of little clinical significance - Often corrects spontaneously during pregnancy or can be everted by simple traction - Important distinction: Acquired nipple retraction is more concerning — may indicate invasive cancer or inflammatory nipple disease - --- CLINICAL PRESENTATIONS OF BREAST DISEASE General point: Greater than 90% of symptomatic breast lesions are benign. Of women with cancer, about 45% present with symptoms; the remainder are detected through mammographic screening. --- 1. PAIN (Mastalgia / Mastodynia)- Common symptom; may be cyclic or noncyclic - Cyclic pain: often due to premenstrual oedema; associated with menstrual cycle - Noncyclic pain: usually localized to one area; causes include ruptured cysts, physical injury, infections — but often no specific lesion is identified - In 5% of cases, the underlying cause is breast cancer — important not to dismiss pain - --- 2. INFLAMMATION- Causes erythema and oedema of all or part of the breast - Rare symptom - Most often caused by infections, which occur primarily during lactation and breastfeeding - Important mimic: Inflammatory breast carcinoma can mimic reactive inflammation — must be excluded - --- 3. NIPPLE DISCHARGE- Small amounts, bilateral = may be normal - Galactorrhea (milky discharge): - - Associated with elevated prolactin (e.g., pituitary adenoma), hypothyroidism, endocrine anovulatory syndromes - Also seen with: oral contraceptives, tricyclic antidepressants, methyldopa, phenothiazines - Repeated nipple stimulation can also induce lactation - Galactorrhea is NOT a feature of malignancy - Bloody or serous discharge: - - Most commonly due to large duct papillomas and cysts - During pregnancy: rapid breast remodeling may produce bloody discharge - Discharge associated with malignancy is most commonly due to ductal carcinoma in situ (DCIS) - Prevalence of malignant cause increases with age: 7% in women under 60; 30% in women 60 and older - Spontaneous, unilateral, bloody discharge in older women — likely malignant --- 4. LUMPINESS / DIFFUSE NODULARITY- Usually a manifestation of normal glandular tissue - When pronounced, imaging studies may be needed to exclude a discrete mass - --- 5. PALPABLE MASSES- Generally detected when 2–3 cm in size - Benign features (~95% of masses): round/oval, rubbery, mobile, circumscribed borders - - Most common benign masses: fibroadenomas and cysts - Malignant features: invade across tissue planes, hard (scirrhous) consistency, irregular borders - Likelihood of malignancy increases with age: - - Under 40 years: 10% chance of malignancy - Over 50 years: 60% chance of malignancy - Location of carcinomas: - - 50% in upper outer quadrant - 10% in each remaining quadrant - 20% in central/subareolar region - About one-third of cancers are first detected as a palpable mass - Screening by palpation alone has little effect on reducing breast cancer mortality — most cancers capable of metastasizing do so before reaching palpable size - --- BREAST IMAGING--- 1. MAMMOGRAPHY- Most commonly used screening test for breast cancer - Introduced to detect non-palpable, asymptomatic carcinomas before metastatic spread - Sensitivity and specificity increase with age: - - Age 40: probability that a mammographic lesion is cancer = 10% - Over age 50: rises to greater than 25% Two principal mammographic signs of carcinoma: Densities: - Breast lesions replacing adipose tissue with radiodense tissue form densities - Rounded densities = usually benign (fibroadenomas, cysts) - Irregular masses = usually invasive carcinoma - Average size of invasive carcinomas detected by mammography: ~1 cm (significantly smaller than those detected by palpation) - Only 15% will have metastasized to regional lymph nodes at time of mammographic detection - Calcifications: - Form on secretions, necrotic debris, or hyalinized stroma - Calcifications associated with benign lesions: apocrine cysts, hyalinized fibroadenomas, sclerosing adenosis - Calcifications associated with malignancy: small, irregular, numerous, and clustered - Introduction of mammographic screening led to a marked increase in diagnosis of DCIS, which is often associated with calcifications - --- 2. DIGITAL BREAST TOMOSYNTHESIS (3D Mammography)- Integrates additional views of the breast - Can detect subtle changes in breast parenchymal texture - --- 3. ULTRASONOGRAPHY- Distinguishes between solid and cystic lesions - More precisely defines the borders of solid lesions - --- 4. MAGNETIC RESONANCE IMAGING (MRI)- Detects cancers via rapid uptake of contrast agents due to increased tumor vascularity and blood flow - Particularly helpful in evaluating dense breasts - --- BREAST PATHOLOGY OVERVIEW — TOPIC OUTLINE (These topics are introduced in the overview and will be covered in detail in subsequent lectures) Fibrocystic Changes- Nonproliferative changes - Proliferative changes - Relationship of fibrocystic changes to breast carcinoma - Inflammatory Processes - Covered separately in lectures - Tumours of the Breast - Fibroadenoma - Phyllodes tumour - Intraductal papilloma - Carcinoma - Lesions of the Male Breast - Gynecomastia - Carcinoma - ---