The accessory tragus is thought to arise from a embryological defect involving the branchial arch. It is often present in a pre-auricular location, but may appear anywhere along the path to the corner of the mouth, or more rarely, over the sternocleidomastoid muscle, as in this case. When in the latter location, some authors use the unflattering term "wattle". This lesion may be confused with a fibroepithelial polyp (acrochordon) or soft fibroma, but the anatomic location and the presence of vellus follicles and cartilage leads to the correct designation.
Histologic sections of skin from a different patient show similar features. There is mild papillomatosis with numerous vellus follicles. In the subjacent tissue, there is fibroadipose tissue and central cartilage.