Development of accessory breast tissue is a consequence the lack of regression remanths of milk line during embryogenesis. These remanths can be found anywhere on the ventral side of the body, extending from the axilla to the pubic region and most of them can be found in the axillary region. On such a tissue may appear almost identical changes that affect the normal breast, from benign non-tumor changes to malignant tumors. In our case report, the case is a 23 year-old woman who had a unilateral solitary lesions in the axilla, which was surgically removed. Starting diagnosis was " Limphadnopathia axillaris lateris sinistri." After removal and histopathological evaluation of the change, it was found that there is a tumor - fibroadenoma. There were also performed immunohistochemical ( IHH ) staining, with finding of a conventional fibroadenoma of the breast as expected. Accessory breast tissue in the axilla is a rare finding, and the tumors in this tissue even rarer. Histopathological confirmation is mandatory, with the need to exclude malignant tumors which are more common in these cases, and they occur at an earlier age.

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