Two days after giving birth, most parents are up to their armpits in nappies; this woman, however, was quite literally up to her armpits in breastmilk — when it suddenly started oozing from her underarm.

The 26-year-old developed pain in her right axilla 48 hours after a normal vaginal delivery.

On examination, doctors noted a firm, round, well-circumscribed mass that expressed a white discharge when pressed (see figure A).

“This finding was consistent with polymastia, a condition in which accessory breast tissue develops along the former embryonic mammary ridge,” the case report authors wrote in The New England Journal of Medicine.