What is the next step in managing a 25-year-old female patient with a 3 cm breast lump confirmed by ultrasound to be a fibroadenoma, who is requesting excision due to concerns?

Management of a 3 cm Fibroadenoma in a 25-Year-Old Woman

Core needle biopsy (CNB) is the next appropriate step for this 25-year-old woman with a 3 cm breast lump confirmed by ultrasound to be a fibroadenoma who is requesting excision due to concerns.

Diagnostic Approach for Fibroadenomas

Fibroadenomas are the most common benign breast tumors in young women. When evaluating a suspected fibroadenoma, the following algorithm should be followed:

1. Initial Imaging: Ultrasound is the first-line imaging for breast evaluation in patients under 30 years 1. This has already been completed in this case, showing a 3 cm fibroadenoma.

2. Next Step - Core Needle Biopsy: Despite ultrasound suggesting fibroadenoma, CNB is indicated in this case because:

   • The mass is 3 cm in size (exceeding the 2.5 cm threshold that increases risk of non-fibroadenoma pathology) 2
   • The patient is requesting excision due to concerns
   • CNB will confirm the diagnosis before proceeding to surgical excision

Rationale for Core Needle Biopsy

The NCCN guidelines recommend tissue sampling via CNB for solid breast masses, particularly when:

• The lesion is large (>2-2.5 cm) 3
• There is patient anxiety or request for removal 4
• To exclude phyllodes tumor, which can mimic fibroadenoma on imaging 3

CNB is preferred over fine needle aspiration due to its superior sensitivity and specificity 1. It provides definitive tissue diagnosis before proceeding with surgical management.

Why Not Other Options?

• Not Option A (Excision after CNB): While this may ultimately be the management path, CNB must be performed first to confirm the diagnosis.

• Not Option B (Mammogram): Mammography is not the first-line imaging for women under 30 years due to dense breast tissue limiting sensitivity 1. Ultrasound has already been performed.

• Not Option D (Monthly self-examination): This is insufficient management for a 3 cm mass with patient concern. The NCCN guidelines indicate that observation alone is only appropriate for lesions <2 cm with low clinical suspicion 3.

Management After CNB

After CNB confirms the diagnosis, management will depend on the pathology results:

1. If confirmed fibroadenoma:

   • Surgical excision is indicated based on:
     • Size >2.5-3 cm 2
     • Patient's request for removal due to anxiety 4

2. If phyllodes tumor or other pathology:

   • Wide local excision with 1 cm margins would be required for phyllodes tumor 3
   • Other pathology would be managed according to specific findings

Important Considerations

• While most fibroadenomas can be managed conservatively, surgical excision is indicated when the mass is >2.5 cm, the patient is symptomatic, or has anxiety about the lesion 4, 2

• The risk of non-fibroadenoma pathology (including phyllodes tumor) increases with size >2.5 cm 2

• CNB before excision helps ensure appropriate surgical planning, especially if the lesion turns out to be a phyllodes tumor requiring wider margins 3