Have a large bulging area on my side/back from a lat dorsi brease reconstruction in August. Normal?

It is common to have axillary (armpit) fullness after a lattisimus flap.  The latissimus muscle is brought through the axilla to get from the back to the breast.  Over time the flap will atrophy (shrink down) and often the axillary fullness goes away completely.  Discuss it with your PS.  I would recommend giving it a full year and if any axillary fullness or skin irregularities remain consider a revision.  Best,Jeremiah Redstone MD

Radiation makes breast reconstruction difficult. I don't blame the plastic surgeon for wanting a lat flap for your reconstruction. These are questions you need to pose to your surgeon. You are only a few month in and you can expect this to take a long time to settle in.

The bulge may be related to the rotation of the muscle or it could be fluid. Best of luck and see your surgeon.

Without in person examination we can ONLY guess to the cause, maybe residual dog ears? Seek these opinions... 

It is not unusual to have bulging on the side/back following a pedicled Latissimus dorsi breast reconstruction.  With time, the muscle should atrophy and the bulging should subside.  If it doesn't the pedicle can be tailored down, but your surgeon will probably want to wait until the flap is well healed.  Discuss your concerns with your surgeon, they should be able to help, but give things time to settle.  Best wishes, Dr. Lepore.