BACKGROUND: Invasive mucinous carcinoma arising in ectopic axillary breast tissue is an uncommon diagnosis. While some published medical literature makes recommendations regarding the management of ectopic primaries, many of these recommendations are outdated. We therefore hope to provide general guidance with the management of this rare entity.

CASE REPORT: We report a case of a 70-year-old woman with primary invasive mucinous carcinoma of ectopic breast tissue. A literature study was performed on primary ectopic breast carcinoma. This case report with review of the literature was performed to provide rationales for a more conservative treatment based upon current data and treatment paradigms. Although the diagnosis of primary ectopic breast carcinoma is uncommon, the presence of a suspicious nodule along the mammary ridge should alert the clinician to consider the possibility of this diagnosis. A mammogram and ultrasound of the nodule were performed and the suspicious nodule was biopsied, confirming the diagnosis. Breast conservation was performed with standard nodal evaluation.

CONCLUSIONS: The management of primary ectopic breast carcinoma should be based upon current breast conservation techniques of orthotopic breast cancer. Current data suggest that standard treatment paradigms remain applicable to this rare clinical entity.

Keywords: Axilla, Adenocarcinoma, Mucinous - surgery, Breast Neoplasms - surgery, Choristoma - surgery