Mom with Engorged Extra Breast Tissue

April 15, 2010

Question
I saw a postpartum woman today with her 5 day-old baby. At about 16-20 weeks into her pregnancy the woman noticed a large lump in her left axilla. Her OB/GYN doctor recommended a biopsy—results showed benign breast tissue. The area continued to grow with the pregnancy and today is roughly the size of a golfball. Milk leaks from the site of entry of the biopsy (which was done in November 2009). No supernumerary nipple is evident. She has a similar but smaller tissue lump in her right axilla. She is incredibly frustrated with the leaking in her armpit. She asked about weaning and wants to take a pill to speed up the process. She said she was committed to breastfeeding until the leaking from the axilla occurred. Can she shut production down in that area only? What do you recommend?

Heather Henry, BSN, RN, IBCLC

Answer
Extra Breast tissue can form in the axilla (under the arms) to a greater degree in some women.  Extra breast tissue responds just like the primary breasts to the hormones of pregnancy and lactation.  Breast tissue under the arms can grow and become engorged. Sometimes this is accessory tissue (separate, additional breast tissue with its own ductal system).  Sometimes these accessory breasts have ductal openings or accessory nipples that drain milk.  Other times the tissue in the so-called tail of Spence and is part of the main breasts.  In such cases, the axillary breast tissue is connected to the main ducts, permitting milk to drain out of the main nipples.

engorgement of the tail of Spence

Yes, she can shut down milk production in the extra breast tissue.  In fact, over time, the milk production will stop on its own.  Weaning in accessory breasts occurs the same way it does in the primary breasts.  For example, if a mom wants to wean “cold turkey” she simply stops breastfeeding or pumping. Unrelieved milk pressure and chemical signals from the retained milk will cause production to cease over the course of a few days to a week.  This is owing to the so-called Feedback Inhibition of Lactation (FIL), a protein in the milk that causes un-drained breast tissue to eventually involute. This is the same mechanism that would allow a mom to wean one breast and still lactate in the other breast.  So, as you see, local control of lactation is entirely possible.

We discuss this issue more fully in our book, The Breastfeeding Atlas, 4th ed. in Chapter 9 (Unusual Presentations of the Breast and Nipple). Figs. 182-185 show photos of engorgement in the tail of Spence and engorged accessory breast tissue.

engorgement of accessory breast tissue

There isn’t a safe weaning pill she can take.  The swelling under her arms and the leaking will resolve on its on.  In the meantime, she can apply cold packs to reduce the swelling.  Postpartum anti-inflammatory pain medicine (ibuprofen) also will help with the swelling.  Within a week or two the tenderness in her axilla should subside, and she can breastfeed without this continuing to be an issue.

By the way, it was prudent of her physician to rule out other issues during her pregnancy.  All lumps should be investigated.

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