Updated: 12/11/2019


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  • A 26-year-old woman presents to the gynecology clinic with a mass in the left breast. She discovered this mass while showering. Her last menstrual period was 10 days ago. There is no family history of breast cancer. On physical exam, you palpate a 3 cm, firm, non-tender mass in the upper lateral quadrant of the left breast. The mass is smooth, well-circumscribed, and mobile. There are no skin changes, nipple discharge, or axillary lymphadenopathy. Ultrasound of the breast was carried out as shown.
  • Clinical definition
    • benign solid tumor of the breast with epithelial and stromal components
  • Epidemiology
    • incidence
      • common in women 15-35 years of age
      • second most common benign breast mass
        • most common breast tumor in women under 30
    • demographics
      • mostly women
      • in males may be associated with anti-androgen treatment
    • risk factors
      • use of oral contraceptives
      • pregnancy
  • Pathophysiology
    • unclear, but partially hormone dependent
      • seen mostly during reproductive years
      • increases during pregnancy
      • regresses during menopause
  • Associated conditions
    • breast cancer
    • phyllodes tumor of the breast
  • Prognosis
    • natural history of disease
      • patient presents with a small, firm, mobile, and non-tender breast lump
        • most small tumors reabsorb
        • rapid increase in size is a cause for concern
          • giant forms (up to 15 cm) have malignant potential
  • Physical exam  
    • firm
    • painless
    • freely movable
    • well circumscribed round breast mass 2-3 cm in diameter
    • does not change with menstrual cycle ("unchanged for three months") 
      • grows slowly in response to estrogen vs rapid change of fibrocystic disease
  • Ultrasonography
    • indications
      • initial diagnostic test for a breast mass in a female under 30 years of age
    • findings
      • reveals a hypoechoic mass with sharp margins
      • can determine if the mass is cystic or solid 
  • Fine needle aspiration or core biopsy of the mass to confirm diagnosis and/or exclude malignancy 
  • Histology
    • proliferative breast lesions without atypia
      • epithelial proliferation occuring in a single terminal ductal unit
      • surrounded by a fibroblastic stroma
      • basement membrane is intact
  • Any enlarging mass warrants excision
  • Fibrocystic disease
    • pain and tenderness varies with menstrual cycle
    • ill-defined mass
  • Breast cyst
  • Galactocele
  • Conservative  
    • observation
      • indication
        • small tumors with slow or no growth rate
          • repeat breast exam and sonogram in 3-6 months
  • Operative
    • surgical excision
      • indications
        • tumors enlarging on follow-up
        • initial presentation of a large mass
        • patient's preference
    • cryoablation
      • an alternative to surgery
      • indications
        • visible on sonogram
        • mass < 4 cm
        • diagnosis confirmed by histology
  • May be a risk factor for future cancer
    • if the fibroadenoma is complex
    • positive family history of breast cancer

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Questions (1)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M2.GN.17.4732) A 16-year-old female presents to her physician’s office after noticing a round lump in her left breast 2 months ago. She reports that the lump seemed to enlarge and became tender just preceding her last 2 menses. It is otherwise painless, and the patient denies any discharge or skin changes. She has no past medical history but her grandmother, age 72, was just diagnosed with invasive ductal carcinoma of the breast. The patient is an avid softball player at her high school and denies alcohol, smoking, or illicit drug use. On exam, the breasts appear symmetric and normal. A 3-cm round, mobile mass is palpated in the upper outer quadrant of the left breast. There is slight tenderness to deep palpation of the mass. There is no axillary lymphadenopathy on either side. Which of the following is the most likely outcome of this patient’s condition? Review Topic | Tested Concept

QID: 108618

This mass will likely require excision




This mass will decrease in size if the patient starts oral contraceptives




This mass slightly increases this patient’s risk of breast cancer in the future




This mass will most likely decrease in size or disappear over time




If this mass grows rapidly to greater than 5 cm, radiation and chemotherapy are indicated



L 3 D

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