Friday, March 17, 2017

Breast Finding Differential Diagnoses

This post is derived from notes I took during training. Any images are copyright their respective owners.


  • Well-circumscribed mass on mammogram (MG)
    • Most common: Cyst, fibroadenoma, lymph node
    • Also: Galactocele, papillary carcinoma
  • High risk lesions
    • Atypical ductal hyperplasia
    • Atypical lobular hyperplasia
    • LCIS
    • Phylloides
    • Radial scar (complex sclerosing lesions)
  • Fluid -containing lesion
    • Invasive cancer
    • Intracystic papillary carcinoma
    • Abscess, hematoma, galactocele, seroma
  • Bilateral breast edema
    • CHF
    • Renal failure
    • Liver disease
  • Unilateral breast edema
    • Subclavian vein occlusion
    • Inflammatory breast cancer
  • Skin thickening
    • Edema (CHF, ARF, liver failure)
    • Acute mastitis
    • Inflammatory carcinoma
    • Locally advanced carcinoma
    • Lymphatic obstruction
    • Radiation therapy


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Wednesday, March 15, 2017

Malignant Breast Disease

This post is derived from notes I took during training. Any images are copyright their respective owners.

  • Most invasive cancers arise from the terminal ductal lobular unit, which contain 100 acini draining into a terminal duct
    • Each breast has 15-18 lobes, each with 20 - 40 lobules
  • Ductal carcinoma in situ (DCIS)
    • Most common subtype
    • Findings: fine, linear, branching ca++ (BIRADS 5)
    • Prognosis: If untreated, 1% per year become invasive
  • Invasive Ductal Carcinoma (IDC)
    • MG: High density, spiculated mass with architectural distortion +/- pleomoprhic or fine linear branching ca++
  • Invasive lobular carcinoma (ILC)
    • Pathology: small monomorphic cells infiltrating stroma single file
    • Difficult to diagnose (21% MG false negative rate) because of infiltrating pattern
    • Findnigs: Spiculated ill-defined mass with architectural distortion; up to ⅓ are bilateral or multicentric (ie, exam contralateral breast well). Ca++ rare.
  • Phyllodes (cystosarcoma phyllodes)
    • Women 40-50s, with large, rapidly growing mass
    • Majority benign, but 25% malignant
    • MG: large, oval or lobular, circumscribed mass
    • US: smoothly marginated mass with heterogeneous echotexture
    • Treatment: wide surgical excision, often recurs
  • Tubular breast carcinoma
    • Pathology: low grade - proliferation of angulated, oval and elongated tubules lined by a single epithelial layer. Spreads through tissue without forming discrete mass - harder to diagnose. Difficult for pathologist to differentiate from radial scar (? spectrum)
    • Findings: small, irregularly shaped, spiculated margins, slow growing
  • Mucinous breast carcinoma
    • Findings: Low density circumscribed mass that can mimic fibroadenoma on US.
    • MR: T2↑
  • Medullary carcinoma
    • Younger women, rare, BRCA1 positive, locally aggressive
  • Papillary breast carcinoma
    • Malignant form of intraductal papilloma
    • Findings: well-circumscribed mass, most likely breast cancer to be associated with a cyst (called intracystic papillary carcinoma)

  • Adenoid cystic breast carcinoma
    • Very rare breast cancer presenting as palpable firm mass. Prognosis good
  • Inflammatory breast carcinoma
    • Presents with breast erythema, edema, firmness
    • Tumor invasion of dermal lymphatics
    • MG: affected breast larger, denser, skin thickening.
  • Lymphoma of the breast: Presents with palpable mass. DLBCL. DI: mass with indistinct margins. Treatment: Chemothearpy / radiation, not surgery
  • Paget disease of nipple:
    • DCIS that infiltrates epidermis of nipple, presents with erythema, ulceration, eczematoid changes
    • Palpable mass worsens prognosis
    • Treatment: breast conservation possible
  • Staging
    • I: Tumor less than 2 cm, negative lymph node (LN)
    • IIA: tumor 2 to 5 cm, negative LN
    • IIB: tumor 2 to 5 cm with ipsilateral LN *OR* >5 cm with neg LN
    • IIIB: any size involving chest wall +/- LN
  • Lymph nodes: based on relationship to pec minor
    • Level 1: lymph nodes lateral to pectoralis minor
    • Level 2: lymph nodes behind the pectoralis minor and interpectoral (Rotter's) nodes
    • Level 3: lymph nodes medial to pectoralis minor
    • Internal mammary chain lymph nodes are not included in this classification.
  • Breast cancer recurrences that occur within 3 yrs (75%) are most likely within original tumor bed; long-term risk 2% for first 10 years, then 1% per year after; mean time to recurrence is 3.5 yrs; most risk: pre-menopausal women with invasion, positive margins, multicentric



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Monday, March 13, 2017

Benign Breast Disease

This post is derived from notes I took during training. Any images are copyright their respective owners.

  • Simple cyst
    • Discard fluid after aspiration unless bloody (in which case, stop and send for cytology)
  • Fibrocystic change - may cause pain in menstruating woman, but essentially normal breast
  • Fibroadenoma - most common palpable mass in young women. Benign neoplasm. Can calcify
    • Giant form: greater than 8 cm
    • Tubular adenoma: variant form, lacks ca++. Circumscribed oval mass.
  • Hamartoma (fibroadenolipoma) - ‘breast within breast’ appearance. BIRADS 2.


  • Sclerosing adenosis - benign proliferative lesion caused by lobular hyperplasia, mimics DCIS
  • Mastitis
    • Nursing mothers or diabetics, presents with breast pain, induration, erythema.
    • Etiology: Most often S. aureus
    • Findings: diffuse skin thickening, edema, adenopathy
    • Treatment: antibiotics
  • Abscess
    • Typically due to S. aureus, can appear like mass
    • Treatment: antibiotics followed by US guided aspiration
  • Intraductal papilloma
    • most common cause of pathologic nipple discharge. 30-50 year old.
    • Benign tumor of lactiferous ducts.
    • Management: ductogram. An adequate ductogram relies on the presence of visible nipple discharge at the time of the procedure. If not seen, cancel and reschedule.
      • Look for filling defect within ducts
    • Treatment: Must excise because papillary carcinoma can appear identical on imaging
  • Periductal / plasma cell mastitis
    • Post menopausal women, due to irritation by intraductal lipids
    • DI: large, rod-like secretory ca++ (BIRADS 2)
  • Duct ectasia
    • A chemical mastitis, not pre-malignant
    • MG: ca++ can be rod-like or central lucencies due to ca++ forming around ducts (secretory ca++)
    • Prognosis: Not pre-malignant, do routine follow-up
  • Diabetic mastopathy
    • Long-term diabetics with firm, painful mass
    • Autoimmune reaction to matrix proteins from chronic hyperglycemia
    • MG: Asymmetry without ca++
    • US: hypoechoic mass
    • Treatment: Needs bx to exclude ca
  • Radial scar (complex sclerosing lesion)
    • MG: linear/radial spiculated appearance with hypolucent lesion
    • Differential diagnosis: carcinoma (dense center), post-surgical scar (not spiculated)
    • Treatment: resection because 30% pre-cancerous


  • Intramammary lymph node
    • Reniform with lucent / hyperechoic hilum, predominantly in upper outer breast
    • Unilateral axillary lymph nodes - exclude breast ca; bilateral enlarged, consider systemic prob
  • Pseudoangiomatous stromal hyperplasia (PASH)
    • Pathology: open slit-like spaces in dense collagenous stroma which are lined by a discontinuous layer of flat, spindle-shaped myofibroblasts with bland nuclei in hormonally active tissue
    • MG: benign mass up to 6cm with no ca++
    • Treatment/Prognosis: benign, but may recur after excisional biopsy
  • Mondor disease: breast superficial thrombophlebitis presenting as tender palpable cord, medial > lateral breast
  • Galactocele - younger pregnant/lactating women, well circumscribed rounded mass with possible fat-fluid level. No need for biopsy
  • Silicone Implants
    • On MR, radial folds extend to periphery, differentiating them from collapsed shell
    • Rupture
      • Intracapsular: MRI: multiple curvilinear low-signal intensity lines within silicone (linguine sign)
      • Extracapsular: US: “snowstorm” appearance of free silicone in breast or axilla (silicone granuloma)
  • Saline implants
    • If ruptured, breast shrinks and saline resorbed.
  • Gynecomastia
    • BIRADS 2 ductal proliferation, can be unilateral or bilateral
    • US: hypoechoic mass behind nipple with finger-like projections
    • MG: Flame-shaped
    • Differential: male breast cancer (lobulated borders, focal mass)
  • Male breast cancer - <1 all="" breast="" ca.="" of="">60s, presents with palpable mass.

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