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Benign Breast Disease & Nipple Discharge

Name: Benign Breast Disease & Nipple Discharge
Creator: Veli Bakalov, MD

Sorting the lumps, leaks, and red breasts that need a biopsy

Surgery·Breast & Endocrine Surgery·6 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

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Fibroadenoma: young woman with a mobile, rubbery, circumscribed mass → ultrasound, biopsy if atypical or growing, then observe or excise.
Phyllodes tumor: rapidly enlarging fibroepithelial mass with leaf-like stroma in a woman in her 40s–50s → wide local excision with negative margins and no axillary surgery.
Breast cyst aspiration: nonbloody fluid with complete resolution needs only a recheck in 4–6 weeks; bloody fluid, a residual mass, or reaccumulation needs imaging and core biopsy.
Fat necrosis after trauma or surgery mimics cancer; biopsy unless imaging shows a classic oil cyst.
Milky bilateral discharge → pregnancy test, prolactin, TSH, and medication review (antipsychotics, metoclopramide).
Spontaneous unilateral single-duct bloody or serous discharge → diagnostic mammogram and ultrasound, then duct excision; intraductal papilloma is the most common cause.
Recurrent subareolar abscess in a smoker is periductal mastitis → antibiotics and drainage, duct excision for a fistula.
Mastitis in a nonlactating woman that fails antibiotics is inflammatory breast cancer until a biopsy proves otherwise.
Gynecomastia is a concentric rubbery disc (drugs, cirrhosis, puberty, hCG tumors—examine the testes); a hard eccentric mass in an older man is breast cancer, often BRCA2-related.

Benign breast masses

Approach. Every palpable mass gets clinical examination, imaging, and tissue sampling when needed, and the three must agree. Ultrasound is the first study under age 30; from about 30, diagnostic mammography is paired with ultrasound. Core needle biopsy is preferred over excision for diagnosis.

Common benign breast masses

Lesion	Typical patient	Clues	Management
Fibroadenoma	Women 15–35	Painless, rubbery, very mobile, well circumscribed; grows in pregnancy, involutes after menopause	Ultrasound ± core biopsy; observe, or excise if enlarging, large, or symptomatic
Phyllodes tumor	Women in their 40s–50s	Rapid growth, often >5 cm; leaf-like stromal fronds; benign to malignant	Wide local excision with negative margins; no axillary staging
Fibrocystic change	Premenopausal women	Bilateral cyclic pain and tender nodularity, worse before menses	Reassurance, supportive bra, NSAIDs; aspirate painful cysts
Fat necrosis	After trauma, surgery, or radiation	Firm, irregular mass with calcifications or skin tethering; oil cyst on imaging	Observe a classic oil cyst; otherwise core biopsy

Fibroadenoma. A proliferation of stroma and glands forming a well-defined mass that moves freely under the fingers. On ultrasound it is oval, circumscribed, and wider than tall. Biopsy is added when imaging is not classic, the mass grows, or the patient is older; involuting fibroadenomas in older women can develop coarse "popcorn" calcifications.

Phyllodes tumor. Overgrowth of cellular stroma pushes leaf-like fronds into cleftlike spaces, and the tumor can stretch the skin over dilated veins. Core biopsy may not separate it from a fibroadenoma, so rapid growth is the key clue. Treatment is wide local excision with negative margins (traditionally at least 1 cm), or mastectomy when the tumor is large relative to the breast. Malignant forms spread hematogenously, mainly to the lung, rather than to lymph nodes, so axillary surgery is not performed. Local recurrence is the main risk after excision.

Fat necrosis. Blunt trauma such as a seat-belt injury, breast surgery, reduction, flap reconstruction, or radiation injures fat, which undergoes saponification. Histology shows necrotic adipocytes, lipid-laden foamy macrophages, and dystrophic calcification. Because the mass can be hard, irregular, and tethered with calcifications, it is biopsied unless imaging shows a classic oil cyst.

Fibrocystic change and breast cysts

Fibrocystic change. The most common benign condition of premenopausal breasts, presenting with bilateral, cyclic pain and lumpiness, often in the upper outer quadrants, that peaks before menses. Cysts, fibrosis, and apocrine metaplasia are nonproliferative and do not raise cancer risk. Pain is treated with reassurance, a well-fitted supportive bra, and topical or oral NSAIDs. A dominant or persistent focal mass still needs imaging.

UltrasoundA simple cyst (anechoic, thin-walled) needs no intervention unless painful; a complex cyst with solid parts needs core biopsy
Aspirate a symptomatic cystClear, yellow, or green fluid with complete disappearance of the mass: discard the fluid
Recheck in 4–6 weeksNo further workup if the mass has not returned
EscalateBloody fluid (send cytology), a residual mass, or repeated reaccumulation → imaging and core biopsy

Nipple discharge

Physiologic versus pathologic discharge

Feature	Physiologic	Pathologic
Laterality and ducts	Bilateral, multiple ducts	Unilateral, single duct
Onset	Only when expressed	Spontaneous
Color	Milky, green, yellow, brown	Bloody or clear-serous
Workup	Pregnancy test, prolactin, TSH, creatinine, drug review if milky	Diagnostic mammogram and retroareolar ultrasound, then duct excision

An associated mass, age over 40, or male sex makes any discharge more concerning.

Galactorrhea. Milky discharge outside lactation reflects prolactin. Exclude pregnancy, then check prolactin, TSH (in hypothyroidism, TRH stimulates prolactin release), and renal function. Review drugs that block dopamine or raise prolactin: antipsychotics such as risperidone, metoclopramide, methyldopa, verapamil, opioids, and estrogens. Chest wall irritation can also trigger it. Hyperprolactinemia without a drug cause calls for pituitary MRI to look for a prolactinoma.

Pathologic discharge. Spontaneous, unilateral, single-duct bloody or serous discharge requires diagnostic mammography and retroareolar ultrasound (ultrasound first under 30). Cytology and occult-blood testing of the fluid do not change management. When imaging is negative and discharge persists, MRI or ductography can localize the lesion.

Intraductal papilloma. A small benign papillary tumor in a subareolar lactiferous duct and the most common cause of bloody single-duct discharge; carcinoma, such as DCIS or papillary carcinoma, accounts for a minority. Excision of the involved duct (microdochectomy or central duct excision) both diagnoses and treats it.

Duct ectasia. Dilated, inflamed subareolar ducts in perimenopausal women produce thick green-black discharge from several ducts, sometimes with nipple retraction and subareolar induration that can mimic cancer.

Inflammatory conditions

Periductal mastitis. In nonlactating women, most of them smokers, squamous metaplasia and keratin plugging of the lactiferous ducts lead to duct rupture, periareolar inflammation, and subareolar abscesses with mixed anaerobic flora. Treatment is an antibiotic covering anaerobes plus ultrasound-guided aspiration or incision and drainage. Recurrent abscesses can form a periareolar mammary duct fistula, which is cured by excising the involved ducts and tract; smoking cessation lowers recurrence. Lactational mastitis differs: it is usually staphylococcal, and breastfeeding continues during treatment.

Mondor disease. Superficial thrombophlebitis of a breast or chest-wall vein, most often the thoracoepigastric, follows surgery, trauma, tight bras, or vigorous exercise. It forms a tender linear cord that tightens into a visible skin groove when the arm is raised. It resolves over weeks with NSAIDs and warm compresses, but age-appropriate mammography is obtained because an underlying cancer is occasionally found.

Inflammatory breast cancer masquerades as mastitis: rapid onset (under 6 months) of erythema, warmth, and edema over at least a third of the breast with peau d'orange, often without a discrete mass, caused by tumor emboli blocking dermal lymphatics. Mastitis in a nonlactating woman that fails 1–2 weeks of antibiotics needs imaging and biopsy, including a skin punch. Treatment is neoadjuvant chemotherapy, modified radical mastectomy without skin sparing, and chest wall radiation.

The male breast

Gynecomastia. A higher estrogen-to-androgen ratio causes a firm, rubbery, concentric disc of glandular tissue beneath the areola, often bilateral and tender early; pseudogynecomastia is fat alone. Causes include puberty (usually resolving within 2 years), drugs (spironolactone, ketoconazole, antiandrogens, anabolic steroids, marijuana), cirrhosis, hyperthyroidism, hypogonadism such as Klinefelter syndrome, and hCG- or estrogen-secreting tumors of the testis. Examine the testes in every case. An adult without an obvious cause needs hCG, LH, testosterone, estradiol, TSH, and liver and renal tests, with testicular ultrasound for a nodule or raised hCG. Stop offending drugs; tamoxifen helps painful recent-onset gynecomastia, and long-standing fibrotic tissue is excised.

Male breast cancer. About 1% of breast cancers, arising in older men as a hard, painless, eccentric subareolar mass, often fixed, with nipple retraction, bloody discharge, or axillary nodes. BRCA2 is the strongest risk factor, followed by Klinefelter syndrome, estrogen exposure, and chest radiation. Diagnostic mammography and ultrasound are followed by core biopsy. Most tumors are ER-positive invasive ductal carcinomas treated with mastectomy and sentinel node biopsy followed by tamoxifen, and every man with breast cancer should be offered germline testing.