Bilateral hamartoma arising in axillary accessory mammary glands. Case report.

A 57-year-old Japanese woman presented with a lump, originally noticed 10 years previously, in both axillary regions. Histologically, the axillary tumors consisted of a random admixture of ducts, lobules and fibrous stroma with predominant adipose tissue. This is the first case of bilateral ectopic hamartoma arising in the axillary regions. Surgeons and pathologists should be aware that ectopic breast hamartoma can occur in both axillary regions.