What type of biopsy is recommended for suspicious gynecomastia?

Biopsy Approach for Suspicious Gynecomastia

For suspicious gynecomastia, image-guided core needle biopsy is the recommended approach after appropriate imaging evaluation has been completed. 1

Diagnostic Algorithm Before Biopsy

Initial Imaging Based on Age

• For men younger than 25 years with suspicious breast findings:

  • Ultrasound is recommended as the initial imaging study 1, 2
  • If ultrasound shows suspicious features, mammography or digital breast tomosynthesis (DBT) should be performed before proceeding to biopsy 1

• For men 25 years and older with suspicious breast findings:

  • Mammography or DBT is recommended as the initial imaging study 1, 2
  • Mammography has high sensitivity (92-100%), specificity (90-96%), and negative predictive value (99-100%) for male breast evaluation 1
  • Ultrasound should follow if mammogram is indeterminate or suspicious 1

Biopsy Technique Selection

Core Needle Biopsy

• Core needle biopsy is superior to fine-needle aspiration (FNA) in terms of sensitivity, specificity, and correct histological grading 1, 3
• Image-guided core biopsy is the procedure of choice for most image-detected breast lesions requiring tissue diagnosis 1
• If a lesion is seen equally well on mammography and ultrasound, ultrasound guidance is preferred due to:
  • Patient comfort
  • Real-time visualization of the needle
  • Absence of ionizing radiation
  • Sampling accuracy 1

Guidance Method Selection

• For lesions visible on ultrasound: ultrasound-guided core biopsy is preferred 1
• For lesions only visible on mammography (e.g., microcalcifications without a mass): stereotactic-guided core biopsy 1
• For lesions only visible on DBT: DBT-guided core biopsy 1

Post-Biopsy Considerations

• A post-biopsy marker clip should be placed to:
  • Confirm tissue sampling of the target lesion
  • Aid in correlation when biopsy was performed with a different imaging modality than initial detection 1
• Post-biopsy imaging should be performed to document marker placement 1

Important Clinical Considerations

When to Proceed Directly to Biopsy

• Suspicious clinical features that warrant biopsy after imaging include:
  • Hard or firm consistency
  • Rapid growth
  • Skin changes
  • Nipple discharge
  • Axillary lymphadenopathy 2, 3

When to Avoid Biopsy

• For classic gynecomastia with typical imaging features, biopsy is not necessary 2, 3
• Unnecessary imaging and biopsy in clear cases of gynecomastia can lead to additional unnecessary procedures 2

Distinguishing Features on Cytology/Histology

• Gynecomastia typically shows:
  • Mixed cell population
  • Cohesive sheets or groups of bland cells
  • Bipolar naked nuclei
  • Single tall columnar cells 4
• These features help distinguish gynecomastia from carcinoma of the male breast 4, 5

Special Considerations

• Male breast cancer is rare (median age 63 years) but should be ruled out in suspicious cases 1, 2
• Higher risk populations requiring more careful evaluation include:
  • BRCA2 mutation carriers
  • Patients with Klinefelter syndrome 6, 7
• Imaging should precede biopsy as post-biopsy changes may confuse image interpretation 1