Discrepant cytologic and radiographic findings in adjacent galactocele and fibroadenoma

Background Clinical, radiologic and pathologic evaluation of a breast mass during pregnancy and lactation often presents a challenge. We report a case of a longstanding benign breast mass that was negative on fine needle aspiration biopsy (FNAB) but somgrapbically appeared suspicious for carcinoma. Case A 41-year-old patient presented with a longstanding benign breast nodule that increased in size postpartum and became painful. The patient was breastfeeding when she developed mastitis in the surrounding area and was treated with antibiotics. The inflammation resolved, but the original mass persisted. FNA of the mass yielded thick, whitish material that on microscopic examination showed clusters of ductal cells with striking reactive, reparative and lactation changes admixed with amorphous material and crystals. The smear pattern was interpreted as negative. However, the sonogram revealed a solid lesion with mixed echogenicity suspicious for malignancy. The patient underwent lumpectomy, which showed concomitant fibroadenoma and galactocele. Conclusion We suspect that in lactating patients preexisting breast masses may interfere with the milk flow, thus rendering the breast tissue around the mass prone to galactocele formation. This may result in erroneous clinical and radiologic impression of growth and transformation of a preexisting lesion.