Why does accessory breast tissue swell before periods?

Yes, accessory breast tissue (extra breast tissue, often found in the armpit area) can respond to hormonal fluctuations just like normal breast tissue, causing swelling or tenderness before menstruation that subsides afterward. It is not unusual for this to occur on only one side. While this cyclical pattern is generally benign, it is advisable to consult a doctor for a proper evaluation to rule out any other underlying conditions.

Yes, axillary breast tissue can behave differently to hormonal changes during menstruation. Sometimes It becomes an aesthetic concern. You should get yourself evaluated properly by your surgeon.

Acessory breast or axillary tail of breast is similar to breast tissue and reacts to hormonal changes. so increase in size and paid during periods or pregnancy are common. If cosmetic issue or pain it can be removed with surgery