Male breast cancer in both breasts linked to Klinefelter syndrome, initially missed

What happened, in summary

A man in his 60s had been diagnosed with cancer in both breasts 4 years before his final admission. He underwent bilateral mastectomy and right axillary-node dissection. The right breast contained a 30 mm grade 2 invasive ductal carcinoma. Cancer was found in 17 of 22 right axillary lymph nodes. The left breast contained ductal carcinoma in situ. The invasive tumor was estrogen receptor-positive, progesterone receptor-positive, and HER2-negative.

After surgery, he received radiation and began letrozole. Two years later, surveillance imaging showed that the cancer had spread to the spine. His disease was then metastatic.

During a later admission, he had severe fluid retention, shortness of breath, weakness, and a major decline in his ability to function. Review of his physical features and testing identified previously unrecognized Klinefelter syndrome. This genetic condition increases the risk of male breast cancer and helped explain the unusual bilateral presentation. The diagnosis also showed that earlier opportunities to recognize his elevated risk had been missed.

By the final stage of the illness, the metastatic cancer had progressed and his estimated prognosis was measured in weeks or less. The palliative-care team focused on relief of breathlessness, swelling, pain, and other symptoms. Active anticancer treatment was no longer the main goal, and care shifted to comfort and end-of-life support.

Klinefelter syndrome often remains unrecognized until adulthood. Earlier recognition could have increased awareness of male breast-cancer risk, although it would not have guaranteed prevention. Seventeen positive nodes showed that the original breast cancer already carried a high risk of distant recurrence.