Clinical and radiologic data and core needle biopsy findings should dictate management of cellular fibroepithelial tumors of the breast.

Fibroepithelial lesions with cellular stroma identified on core needle biopsy (CNB) may prove to be either fibroadenoma or phyllodes tumor at excision; therefore, management of these rare lesions is highly controversial. We aim to assess the management and the outcome of 101 cellular fibroepithelial lesions diagnosed on CNB over a 6-year period in one institution. Consensus on clinical management in each individual patient was reached during multi-disciplinary conferences, based on careful correlation of clinical data with results of imaging studies and pathology of CNB samples. Radiologic findings (mammogram and sonogram) and multiple histologic parameters on CNB specimen were blindly re-evaluated by one experienced breast radiologist and two breast pathologists, respectively, and results were correlated with final diagnosis at excision. Cellular fibroepithelial lesions with indeterminate or suspect imaging findings, with larger size, and with an equivocal comment such as "cannot rule out phyllodes tumor" in the pathology report were excised more frequently (p = 0.05, p = 0.034, and p = 0.01, respectively). Of 43 excised lesions, 13 were classified as benign phyllodes tumors, 23 as fibroadenoma and seven as benign cellular fibroepithelial lesion. The final diagnosis at excision did not significantly correlate with any clinical data, or with retrospective evaluation of imaging findings or comprehensive evaluation of multiple histologic parameters. In 58 patients who had clinical and radiologic follow-up (mean ± SD: 30 ± 21 months) there was no evidence of disease progression. No clinical and radiologic findings and/or comprehensive evaluation of multiple histologic parameters on CNB specimen are distinctive enough to predict final classification of equivocal cellular fibroepithelial lesions. However, careful clinico-pathologic and radiologic correlation may help to select the most clinically significant lesions for proper immediate surgical management. Follow-up alone may be an appropriate alternative for a subset of patients, given a good clinical, pathologic, and radiologic correlation.