Fig. 1

US of the left axillary region. A Longitudinal image of the solid, heterogeneous, elongated, irregular lesion, with alternating echogenicities arranged in layers (pink arrow), forming the tail sign (green arrow) along the longest axis. B Extended view of the aforementioned lesion, showing digitiform extensions that extend to adjacent adipose planes (blue arrows). C Transverse image of the tumor, showing alternating echogenicity layers (pink arrow) as well as signs of invasion of the coracobrachialis muscle (white arrow). D There was no vascularity detectable in the color Doppler mode