Introduction
Ectopic accessory breast tissue can occur anywhere along the embryonic
mammary line and is found in 2‑6% of the general population.(1) Though
rare, cancer can arise in ectopic breast tissue, with 70-80% of these
cases arising in the axillary region.(2) Once detected, ectopic breast
cancer is managed under the same principles as orthotopic breast cancer.
One approach involves the option of wide local excision with sentinel
lymph node (SLN) biopsy followed by radiation therapy. However, SLN
mapping and biopsy in axillary breast cancer can be challenging due to
the proximity of the primary tumor to the axillary lymph nodes. Few
studies have described the injection technique of radionuclide tracer
dye in the setting of axillary breast cancer. Here, we describe a case
of primary axillary breast carcinoma in which concurrent peri-tumoral
and intra-tumoral injection of radionuclide tracer allowed for
successful identification of SLNs. This report serves to detail the
approach to SLN identification in this clinical situation and adds to
the growing body of evidence documenting the feasibility of SLN mapping
and biopsy in ectopic breast carcinoma.