[Axillary lymph node metastases with an occult breast: About 16 cases from a cohort of 7770 patients]

Isolated axillary lymph node metastases is an unusual clinical presentation of breast carcinoma. We studied its different issues.This study is a follow-up study of 16patients, treated between 1996 and 2012, presenting with axillary metastases with an occult breast carcinoma, which could not be identified by physical examination nor by a conventional imaging or a breast MRI. Clinical characteristics, histological analysis, treatment, monitoring and five-year survival rate were studied.The incidence of this kind of breast cancer was 0.20%. A breast MRI was performed in 75% of the patients. The histology of these tumors showed a rate of hormono-sensibility of 50% and an HER2 overexpression of 44%. Sixty-nine percent of the patients had no breast surgery or radiotherapy; global five-year survival rate for these women was 77.4%±11.5.The survival rates of this study should lead the practitioner to choose a less aggressive breast therapy. Moreover, the histological characteristics explain the high metastatic potential of these tumors, and relate them to the HER2+ subclass of gene expression patterns of breast carcinomas.