Invasive Ductal Carcinoma Arising in Borderline Phyllode Tumor: A Potential Role of PIK3CA Mutation

INTRODUCTION: Carcinomatous lesions associated with phyllodes tumors are extremely rare and are found in less than 1% of all cases. To date, the molecular biological mechanisms associated with this carcinomatous transformation remain unknown. PRESENTATION OF CASE: We present here the case of a 61-year-old patient with invasive ductal of no special type (NST) carcinoma originating in a borderline phyllode tumor with mutation in the PIK3CA gene. DISCUSSION: To the best of our knowledge, this mutation has never been described in this type of association. CONCLUSION: Based on these data, we can better understand the ethiopathogenic molecular mechanisms in this type of lesion. Consequently, they could also in the future give rise to new therapeutic alternatives. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of IJS Publishing Group Ltd.