Objective: Complex fibroadenomas are a fibroadenoma subtype harboring one or more complex features. We sought to evaluate the incidence of complex fibroadenoma on biopsy and to propose decision criteria for managing patients with these breast lesions.
Materials and methods: Complex fibroadenomas were diagnosed in 63 of 401 fibroadenomas (15.7%) found at consecutive percutaneous needle or excisional surgical biopsy. We evaluated the clinical and imaging presentations of complex fibroadenomas; compared pathology at core and excisional biopsy; and contrasted age, pathology, and size of complex and simple fibroadenomas using the Student's t test.
Results: Patients with complex lesions were 18.5 years older (median age, 47 years; range, 21-69 years) than patients with noncomplex fibroadenomas (median age, 28.5 years; range, 12-86 years) (p < 0.001). Complex fibroadenomas were half the size (average, 1.3 cm; range, 0.5-2.6 cm) of noncomplex fibroadenomas (average, 2.5 cm; range, 0.5-7.5 cm) (p < 0.001). Only one malignancy, an invasive lobular carcinoma, was found in 63 complex fibroadenomas (1.6%). This patient had atypical lobular hyperplasia at core needle biopsy.
Conclusion: Approximately 16% of fibroadenomas are complex. Complex fibroadenomas are smaller and appear at an older age. At a mean follow-up of 2 years, we found a low incidence of malignancy in complex fibroadenomas. Women with complex fibroadenomas may therefore be managed with a conservative approach, similar to the approach now recommended for women with simple fibroadenomas.