Axillary accessory breast associated with galactorrhea in an adolescent girl.

We present herein a case of right axillary accessory breast associated with galactorrhea in an adolescent girl. A 14-year-old Japanese girl presented with an 11-month history of a tender, subcutaneous lesion in the right axillary fossa. Seven months later, she experienced menarche. Subsequently, the patient noticed pressure-induced galactorrhea from both nipples. Physical examination revealed an elastic, firm and well-demarcated subcutaneous tumor 3 × 2 cm in size. A biopsy specimen showed proliferation of mammary gland tissue in the stroma located below the subcutaneous fat tissue. On the basis of these findings the patient was diagnosed with an accessory breast. Interestingly, the galactorrhea ceased after surgical removal of the accessory breast.