Ductal carcinoma in a multiple fibroadenoma: diagnostic inaccuracies

We present the diagnostic inaccuracies encountered in a case of multiple fibroadenoma with malignant transformation. A 30-year-old lady presented with lump in the right breast of one month duration which on clinical examination, X-ray mammogram, sonomammogram were suggestive of multiple fibroadenomas. Fine needle aspiration cytology of the largest lump revealed features of malignancy and a core biopsy showed pleomorphic cells that could not be categorized. Due to the clinical, radiological and pathological diagnostic ambiguity, lumpectomy was performed and frozen section showed features of only conventional fibroadenoma. Representative bits on routine processing showed only features of fibroadenoma. Hence, complete submission of all lumps was done, which revealed fibroadenoma with invasive ductal carcinoma in one. Patient underwent modified radical mastectomy which showed multiple fibroadenomas, focal fibrocystic disease with a focus of residual invasive tumor and metastatic deposit in one axillary lymph node. This case report highlights the diagnostic challenges in detecting malignancy in fibroadenoma and a need for extensive tissue sampling in multiple fibroadenomas to detect the rare occurrence of carcinoma.