What is a fibroadenoma?

Fibroadenoma: Definition and Management

A fibroadenoma is the most common benign breast tumor, typically presenting as a smooth, rubbery, mobile mass in women under 40 years of age. 1

Types of Fibroadenomas

• Fibroadenomas can be classified as simple, complex, giant, myxoid, or juvenile 1
• Giant fibroadenomas exceed 5 cm in diameter, weigh more than 500g, or replace more than four-fifths of the breast 2
• Juvenile fibroadenomas occur during childhood or adolescence, with a mean presentation age of 13.92 years 2
• Complex fibroadenomas contain cysts >3mm, epithelial calcifications, sclerosing adenosis, or papillary apocrine metaplasia 3

Clinical Presentation

• Present as smooth, rubbery, mobile masses on palpation 1
• Typically unilateral 3
• May grow rapidly during hormonal changes such as pregnancy 3
• Can cause breast asymmetry or compression of surrounding breast tissue when large 3

Diagnostic Evaluation

• Ultrasound is the preferred imaging method for women under 30 years with a palpable mass 4
• Mammography should be added for women 30 years or older 4
• Benign ultrasound features include oval or round shape, well-defined margins, homogeneous echogenicity, and parallel orientation to the chest wall 4
• Core needle biopsy is preferred over fine needle aspiration for better sensitivity, specificity, and histological grading 4

Management Approach

• Most fibroadenomas can be managed conservatively with observation 4
• Surgical excision is indicated when one or more of the following are present:
  • Size greater than 2-2.5 cm 4, 5
  • Rapid growth rate 1
  • Complex features 1
  • Patient anxiety or request for removal 4
  • Symptoms from the mass 1
  • Age >35 years 5
  • Immobile or poorly circumscribed mass 5
  • Biopsy not definitive for fibroadenoma 5
  • Suspected phyllodes tumor 4

Important Considerations

• The risk of malignancy in or adjacent to a fibroadenoma is very low (0.58% in one study) 6
• The risk of cancer in a growing fibroadenoma is even rarer 6
• Distinguishing between fibroadenoma and phyllodes tumor can be difficult on imaging or even core biopsy 4
• Fibroadenomas with abnormal epithelial features require excision 6
• Fibroadenomas without epithelial abnormality diagnosed by core biopsy need no specific follow-up due to negligible risk of malignant transformation 6

Follow-up

• If pathology confirms benign fibroadenoma, routine breast screening is recommended 4
• If pathology reveals atypical features, follow appropriate risk reduction guidelines 4
• Surgical intervention during pregnancy may be necessary for rapidly growing fibroadenomas to prevent permanent breast tissue damage 3