Invasive Cancer Confined to the Nipple of the Conserved Breast: A Case Report

Invasive breast cancer deriving from the milk duct and lobule that develops in the nipple is extremely rare, except in Paget's disease and skin cancer. This is the second reported case of the development of invasive cancer confined to the nipple after breast-conserving surgery. A 69-year-old woman visited our department due to redness, swelling, and bloody discharge of the right nipple in the last month. A needle biopsy was suggestive of invasive ductal carcinoma; we performed a removal surgery of the right residual breast tissue and a second sentinel lymph node biopsy. She underwent these procedures 10 years previously as well. Thus, we diagnosed the present lesion as a local recurrence, but it was unknown whether the lesion was a true recurrence or second cancer, namely, metachronal ipsilateral breast cancer. The present case helps promote awareness that invasive cancer rarely develops in the nipple after conserving surgery. Patients should be encouraged to visit a medical facility if experiencing skin changes and swelling of the nipple. Additionally, breast cancer patients must be carefully selected for breast-conserving surgery; failure to do so may later result in nipple-specific local recurrence.