Breast fibroadenomas in the pediatric population: common and uncommon sonographic findings.

Background: Sonography is usually requested to evaluate palpable pediatric breast lumps, and solid masses are almost always fibroadenomas. Lack of familiarity with the findings of fibroadenomas can lead to diagnostic uncertainty and sometimes unnecessary biopsy and excision. We sought to review the spectrum of sonographic findings in our cases of pathology proven pediatric fibroadenomas.

Objective: The purpose of this retrospective study was to describe the sonographic appearances of pathologically proven pediatric breast fibroadenomas.

Materials And Methods: A query of the Department of Radiology database at our institution was performed for all patients younger than 19 years who underwent breast US from January 2001 to June 2009. A total of 332 patients were identified: 282 girls (85%) and 50 boys (15%). Ninety-one girls and no boys had a solid breast mass based on US findings. Forty-three children had a total of 49 pathologically proven breast masses with the diagnoses of fibroadenoma (44), hamartoma (1), non-Hodgkin lymphoma (1), tubular adenoma (1), pseudoangiomatous stromal hyperplasia (1) and lactation changes (1). Reviews of medical records, histological results and sonographic examinations of all pathology-proven fibroadenomas were performed. US findings were characterized according to location, multiplicity, size, shape, echogenicity and homogeneity, definition of margins, posterior acoustic features and Doppler vascularity.

Results: The vast majority of solid breast masses in girls are histologically benign. Fibroadenomas accounted for 91% of the pathologically proven solid breast masses. Common findings on US imaging are an oval shape, hypoechoic echo pattern, posterior acoustic enhancement and internal Doppler signal. Lobulations were found in 57% of the masses. Less common findings are absent internal vascular flow and complex echo pattern, while isoechoic echo pattern, posterior shadowing and angular margins are rare or unusual.

Conclusion: Fibroadenomas represent the most common solid mass in the breasts of girls. Sonographic appearances are usually characteristic and do not significantly differ from those found in adults. The radiologist must be aware of common and uncommon sonographic appearances of fibroadenomas in the pediatric age group and should be cautious when recommending histological confirmation based on imaging findings, as breast malignancy is extremely rare.