What is the management approach for myxoid fibroadenoma?

Management of Myxoid Fibroadenoma

A conservative "watch and wait" strategy is the recommended first-line approach for newly diagnosed myxoid fibroadenomas, regardless of whether the patient is experiencing pain or other clinical symptoms. 1

Diagnosis and Evaluation

• Myxoid fibroadenoma is a variant of fibroadenoma with distinct myxedematous changes that can mimic other conditions including mucinous carcinoma 2
• Initial evaluation should include breast ultrasound, which is the preferred imaging modality for women under 30 years with a palpable mass 3
• For women 30 years or older, mammography should be performed in addition to ultrasound 3
• On ultrasound, myxoid fibroadenomas typically show:
  • Higher depth-to-width ratio (0.79 ± 0.26) compared to non-myxoid fibroadenomas (0.64 ± 0.26) 2
  • Relatively round shape 2
  • Increased posterior echo enhancement 2
  • Internal hyperechogenicity 2

Management Algorithm

Initial Approach

• Implement a "watch and wait" strategy for 1-2 years with regular follow-up using contrast-enhanced MRI 1
• First clinical and radiologic re-evaluation should be performed within 8-12 weeks after diagnosis 1
• Subsequent evaluations should be conducted every 3 months during the first year 1
• Follow-up can then be reduced to every 6 months up to the fifth year, and yearly thereafter 1

When to Consider Active Treatment

Active intervention should be considered when:

• There is objective tumor size progression in multiple consecutive imaging studies 1
• The patient experiences worsening pain or functional limitation 1
• The lesion shows rapid growth or compression of adjacent structures 1
• The mass is larger than 2 cm 4
• There are complex features suggesting possible malignancy 4
• The patient experiences significant anxiety about the lesion 4

Treatment Options

When intervention is deemed necessary:

• Surgical excision is the standard treatment for myxoid fibroadenomas that meet criteria for removal 4
• The procedure should be performed by a surgeon specifically trained in breast procedures 5
• The standard surgical approach is a wide excision with negative margins 5

Special Considerations

• Myxoid fibroadenomas may be more likely to be misdiagnosed as suspicious for malignancy due to their sonographic features 2
• Among fibroadenomas suspected of malignancy that showed rapid growth and/or size greater than 3 cm, a high proportion (16 out of 17 in one study) were found to be myxoid fibroadenomas 2
• Understanding the histologic and sonographic features of myxoid fibroadenomas can help reduce unnecessary biopsies 2
• Long-term studies of fibroadenomas managed conservatively show that approximately 52% reduce in size, 16% remain unchanged, and 32% grow over a 5-year period 6
• No cases of carcinoma developing at the site of a presumed fibroadenoma were reported in long-term follow-up studies 6

Caution

• Distinguishing between fibroadenoma variants and other breast lesions can be challenging, even with needle aspiration or core biopsy 3
• Triple assessment (clinical examination, imaging, and pathology) is essential for accurate diagnosis 4