How to rid seroma one year after tummy tuck? Can it be removed with lipo or is lipo to it more dangerous?

Typically I find the best way to deal with this is to open the area, cut out the psuedobursa in its entirety, put drains in, and let it heal.  Anything else is less effective.

After such a long time after
the seroma, the treatment need to be carefully evaluated. If is not symptomatic observation with a
compression garment needs to be consider. If is associate
with pain or a deformity a drain or open
of the seroma needs to be done.

The simple treatment would be to percutaneously aspirate it, and hope it does not come back. If it recurs, then operative treatment with excision of the seroma bursa and drainage with JP tubes like you had with your tummy tuck. Good luck and thanks for sharing.

Surgical excision is more definitive, but inserting a drain for several weeks might be effective if surgery is not a good option.  The potential for infection needs to be considered, and antibiotic coverage should be used in order to minimize this possibility.

A seroma cavity that is a year out is usually "walled off" and may need more than a JP drain to eliminate it. Liposuction is not a solution nor revision abdominoplasty unless it is warranted to remove the seroma cavity along with its wall. 

The pocket of fluid will have scar tissue around it. It cases where it is long standing and the pocket does not collapse and resolve, the tissue needs to be removed and a drain placed. Lipo is NOT a solution.