1 year question after breast reduction; marble sized knot at the Center of the T closure?

I am sorry to hear about the problem you are experiencing but I am happy to hear that you are undergoing a workup and biopsy. In other words, best not to assume that the lesion is  related to the previous breast reduction surgery. Having said that, it is most likely that the results of the biopsy will show fat necrosis plus/minus scar tissue. Best wishes.

It is sensible to have a core biopsy, but this sounds like an area of fat necrosis which then does feel harder than the surrounding tissues. The fat dies back when it does not have enough blood supply, and the area furthest from the original blood supply of the breasts is the tissues around the T closure, so is a more common area for fat necrosis to occur.

It sounds that you may have some fat necrosis in your healing breast reduction surgery.

These are not serious, but need excision to remove them.