Adenoid Cystic Carcinoma of the Breast Associated With Invasive Duct Carcinoma: A Case Report

A case of adenoid cystic carcinoma (AdCC) of the breast containing areas of “ordinary” duct carcinoma, invasive and in situ (IDC-DCIS), with lymph-node, bone and lung metastases is reported. On histology, the tumour showed the typical features of AdCC, intermingled with IDC- DCIS, both expressing c-KIT. From a nuclear genomic point of view, both AdCC and DCIS revealed some com- mon genetic alterations identified by array comparative hybridization (aCGH): deletions in 1q24.1, 16p, 19q13. and amplifications in 4p, 8q24.23, 20q11.22. The two invasive components shared the following aberrations: deletions in 1p36, 3p22, 6p12, 9q31.3, 16p, 19p13.2, 19q13 and amplifications in 4p16, 6p22, 11q12.3, 14q32, 20q13. The present case differs from AdCC previously reported in the breast as it shows overgrowth of an “ordinary” duct carcinomatous component, a phenomenon previously seen in the salivary glands and called “AdCC with high grade transformation”. The case shows aggressive behaviour.