Ectopic Breast Cancer Mimicking an Epidermal Inclusion Cyst: Case Report with Review of the Literature

Ectopic breast cancer is a relatively rare entity, (0.3-0.6% of breast cancer), affecting mostly women.It usually appears along the milk lines, from the axilla to the groin, while it can be found in distant locations as well.A total of 299 cases have been reported.In this paper, a case of ectopic breast cancer of the axilla is reported, mimicking an epidermal inclusion cyst, initially treated with local resection, and almost being overlooked.After diagnosis was made, wide excision followed, with sentinel lymph node biopsy.Pathology revealed infiltrative ductal carcinoma of the breast, with site of in-situ ductal carcinoma.Ectopic breast cancer constitutes a challenging entity due to difficulty in diagnosis, which can be easily overlooked and therefore delayed, and the patients are usually diagnosed at a more advanced stage.Dealing with such cases is usually complex and should be performed at expert centers to achieve the best results.