There are many stories of the odd bodily changes some women experience after childbirth but even doctors were intrigued by the case of a woman lactating from her armpit.
The 26-year-old Portuguese woman reported feeling pains in her armpit two days after giving birth.
A report published in The New England Journal of Medicine stated that upon close examination, doctors found a round mass in her armpit.
According to the report, the mass ‘released a white discharge when pressed’— a discharge which turned out to be breast milk.
After further investigation, the team of medics at the Hospital de Santa Maria in Lisbon, Portugal, diagnosed the woman with polymastia:
...a condition in which accessory breast tissue develops along the former embryonic mammary ridge.
This additional tissue grows as a result of embryonic development when the cells that become mammary glands are forming a line from the armpit to the groin.
The condition happens during fetal development, usually disappearing everywhere except for the breast.
The most common location for accessory breast tissue is the armpit.
Rare but not novel
Research suggests that between 2% and 6% of women are born with additional breast tissue.
People may not realise they have the accessory breast tissue until they become pregnant or start breastfeeding if the site does not have a nipple or areola.
Some women can even pump breast milk from the accessory breast tissue.
In a 1999 paper, researchers describe the case of an 18-year-old woman with accessory breast tissue in the armpit who was able to successfully pump axillary breast tissue for eight weeks to relieve discomfort and continue breast-feeding.