Giant fibroadenoma

Case contributed by Dr Ammar Ashraf

Presentation

Diffuse left breast swelling for 1 year. Increasing in size for the last three months.

Patient Data

Age: 12 years
Gender: Female

Left breast is replaced by a large homogeneous isoechoic to mildly hypoechoic mass. Increased vascularity is seen in this left breast mass on color doppler ultrasound examination. Right breast is normal. 

Findings: A large well-defined lobulated solid mass measuring about 14 x 12 x 11 cm is seen in the left breast. Multiple branching fibrotic bands are seen within this mass. No spiculations, cystic areas or obvious calcifications are seen in it. The overlying skin is stretched but not thickened. No nipple retraction is noted. No evidence of infiltration of the underlying pectoral muscles. No significant left axillary lymphadenopathy is seen. Mass shows significant enhancement on the dynamic post-contrast scan with type I curve. Right breast is unremarkable. Impression: Large well-defined, lobulated solid left breast mass with benign enhancement curves. Possible differential diagnoses include giant fibroadenoma and phyllodes tumor.

Procedure: Left simple mastectomy.  Gross: Specimen received in formalin weighing about 853 grams. A rounded bulbous mass measuring 14 x 12 x 10 cm is seen under the skin. Serial slicing shows a well-circumscribed fleshy lobulated pink mass. The consistency of the tumor is firm and no obvious areas of necrosis are seen.  Microscopy: Uniform picture comprising proliferating ducts in fibrocollagenous connective tissue stroma. There is prominent epithelial proliferation, but the stroma is less cellular and no cytological atypia or necrosis is seen.

Diagnosis: Giant fibroadenoma. No malignancy is seen. 

Case Discussion

The primary breast malignancy is quite uncommon in the pediatric population. Only 0.1% of primary breast malignancies occur in children and adolescents (< 1% of pediatric malignancies) 1. Fibroadenoma (benign fibroepithelial tumor) is the commonest breast mass in the pediatric population and in this age group, the commonest differential diagnosis of fibroadenoma is the phyllodes tumor, which is usually a benign tumor but can occasionally be malignant 1. Pre-operative discrimination between fibroadenoma and phyllodes tumor is strenuous due to the considerable similarities in their clinical, radiological, and pathological features 1. Fibroadenoma is a BI-RADS category 3 lesion. In the pediatric population, the treatment of the solid breast masses depends upon their size. For example, the breast mass with classical imaging features of a fibroadenoma and measuring less than 5 cm in size at initial presentation can be followed up sonographically and the biopsy is recommended for the lesions showing interval growth of ≥50% during follow-up or the lesions measuring more than 5 cm at the initial presentation 1.  

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