A Pain in the.....Shoulder?

During my routine searching through the recent literature on endometriosis I happened upon an article that got my attention. If you follow the link you’ll see there isn’t much there, merely a report of right shoulder pain which was later found to be due to endometriosis. That’s unusual in itself but I realised that’s not the first time I’ve heard a report like this. Doing some further searching I found papers referring to endometriosis of the diaphragm. Endometriosis of the diaphragm can lead to a condition known as catamenial hemothorax, where blood accumulates in the pleural cavity (the part in your chest where your lungs are).

Although cases of diaphragmatic endometriosis are rare, I found about eight papers describing the phenomenon, most of which described cyclic right shoulder pain as an indicator of endometriosis of the diaphragm. Why pain in the right shoulder should be an indicator of endometriosis in a completely different part of the body I’m not sure. How endometriosis comes to be on the diaphragm as well is somewhat of a mystery. There are theories which suggest endometriosis can travel or ‘metastasise’ around the body. Others think that patches of endometriosis are formed around the body whilst you are in utero (i.e. still in the womb) and lay dormant until something triggers them to develop into endometriotic implants. Unfortunately there is no certain conclusion yet, but as soon as there is I’ll let you know, whatch this space.