What is the first line of imaging for tumors causing gynecomastia?

First Line Imaging for Tumors Causing Gynecomastia

High-frequency (>10 MHz) testicular ultrasound is the first-line imaging modality for evaluating tumors causing gynecomastia. 1

Diagnostic Approach

Initial Clinical Assessment

• Most men with breast symptoms can be diagnosed based on clinical findings without imaging 2
• Clinical examination should include both breasts, abdomen, supraclavicular fossae, and chest to identify gynecomastia 1
• Testicular examination is essential as testicular tumors can cause gynecomastia through hormonal mechanisms 3
• Differentiate true gynecomastia (glandular tissue) from pseudogynecomastia (fatty tissue), especially in patients with elevated BMI 2

When to Pursue Imaging

• Imaging is not routinely recommended for cases with clear clinical findings consistent with benign gynecomastia 2
• Imaging should be pursued when:
  • Differentiation between benign disease and breast cancer cannot be made clinically 2
  • Clinical presentation is suspicious for malignancy 2
  • There is suspicion for an underlying testicular or adrenal tumor 3, 4

Imaging Algorithm by Age and Presentation

For Testicular Imaging (Primary Focus)

• High-frequency (>10 MHz) testicular ultrasound is recommended as the first-line imaging modality for suspected testicular tumors causing gynecomastia 1
• Testicular ultrasound has higher sensitivity than physical examination alone for detecting testicular tumors 3
• Testicular ultrasound can determine if a mass is intratesticular or extratesticular, the size of lesions, and detect multifocal disease 1

For Breast Imaging (When Needed)

• Men younger than 25: Ultrasound is the initial recommended breast imaging study 2
• Men 25 and older: Mammography or digital breast tomosynthesis is recommended 2

For Adrenal Tumors

• Adrenal tumors can secrete estrogen directly, causing gynecomastia 5, 6
• Ultrasonography may be valuable in identifying adrenal tumors causing gynecomastia, particularly in prepubertal cases 6

Laboratory Evaluation to Guide Imaging

• Serum tumor markers should be obtained before orchidectomy, including:
  • Alpha-fetoprotein (AFP) 1
  • Human chorionic gonadotropin (hCG) 1
  • Lactate dehydrogenase (LDH) 1
• Additional hormonal evaluation may include testosterone, estradiol, SHBG, LH, FSH, TSH, and prolactin 3
• Abnormal hormone levels may guide the focus of imaging studies 3

Special Considerations

• Testicular sex cord tumors are an increasingly recognized cause of prepubertal gynecomastia and require testicular ultrasound for diagnosis 4
• Patients with Klinefelter syndrome have a significantly increased risk of gynecomastia (relative risk of 24.7) and may require more thorough imaging evaluation 5
• BRCA2 mutation carriers have a higher risk of male breast cancer and gynecomastia, which may influence the imaging approach 5

Common Pitfalls to Avoid

• Unnecessary imaging in clear cases of gynecomastia can lead to additional unnecessary benign biopsies 2
• Failing to perform testicular ultrasound when physical examination is normal, as testicular tumors may be small and non-palpable 3
• Relying solely on physical examination to detect testicular tumors, which has low sensitivity 3
• Not considering adrenal tumors as a potential cause of gynecomastia, particularly in prepubertal cases 6