What happened, in summary

A 36-year-old woman with a pathogenic BRCA2 variant underwent bilateral nipple-sparing mastectomy in May 2021. The left side was treated for a known node-positive breast cancer, while the right mastectomy was performed for hereditary-risk reduction.

Pathology unexpectedly found a separate 6 mm invasive cancer in the right breast together with extensive ductal carcinoma in situ. The right-sided invasive cancer was hormone receptor-positive and HER2-negative and had not been detected before surgery. This represented a distinct right-sided primary cancer, separate from the known left-sided tumor.

The right breast was removed with immediate reconstruction as part of the bilateral procedure. At the woman’s 17-month follow-up after bilateral surgery and adjuvant treatment for her left-breast cancer, she was free from disease and reported good quality of life and satisfaction with her reconstruction.