Fibroadenomas

Fibroadenomas are the most common benign solid tumors of breast tissue. They may develop at any time after puberty, but they are found most frequently in women in their 20s and 30s and are more common than cysts among women aged 25 or younger.

Fibroadenomas may also be seen in postmenopausal patients; however, these tumors usually develop before menopause and become clinically apparent only with involution of surrounding breast tissue. In the United States, fibroadenomas occur more frequently in African American women than among other women.

Clinically, fibroadenomas are painless, well-circumscribed, freely moveable tumors with a rounded, lobulated, or discoid configuration visible on mammography (A). They have a characteristic ultrasonographic appearance that includes sharp borders, uniform internal echoes, and a width that is greater than the height (B).

The advent of high-definition ultrasound and harmonic imaging has expanded the role of ultrasound in breast imaging. While originally ultrasound could simply distinguish cysts from solid tumors, these more advanced techniques can help characterize solid masses as benign, indeterminate, or malignant. For diagnosis, correlation between mammographic and sonographic findings is essential.

A number of factors may affect management of fibroadenoma, including the size of the tumor and its palpability, as well as your patient's age, family history, and level of anxiety. If the sonogram clearly demonstrates findings characteristic of fibroadenoma, you can either follow up with regular reexaminations (usually every 6 months to 1 or 2 years) or obtain a tissue diagnosis by fine-needle aspiration biopsy or core biopsy.

Your patient's age will usually be a major factor in deciding whether reexamination or biopsy is the most appropriate strategy. For women aged 25 or younger, observation is the preferred course. For women older than 35 for whom the fibroadenoma represents a new finding, tissue diagnosis is advisable.

Consider doing a biopsy if it will help relieve patient anxiety and/or you think a histopathologic examination is advisable to confirm that the tumor is benign. Biopsy may also be called for if your patient is unable or unwilling to adhere to a follow-up examination or examinations at short-term intervals.

Fibroadenomas are responsive to hormone levels and may increase in size toward the end of each menstrual cycle. Pregnancy may induce rapid and considerable enlargement of these tumors, which can be a cause of concern for both you and your patient. Consider obtaining a biopsy for such cases as well. C illustrates needle biopsy of an enlarged tumor, which was eventually diagnosed as a benign lactating adenoma.