[2][3][4] A recent publication has presented an updated description of the anatomy of the breast and upper outer chest, calling into question the concept of an axillary tail.

[7][8] Since 1871, a notion evolved of a tail-like extension of fatty tissue originating from the upper outer portion of the breast and traveling into the axilla.

[9] However, for anatomic clarity, oncologists and surgeons may want to consider that the adjacent but separate axillary mound is not a tissue extension of the primary breast.

Instead, there is a growing awareness that separate focal vestigial breast mounds are consistently present in adults, located in pairs running down the curved lines of the embryological mammary ridges.

[10] It may be of great oncologic and surgical benefit if breast cancer formation and metastasis were reinterpreted in light of this new anatomic understanding.