Why can't my doctor drain my seroma with a syringe? (photos)

I went to my doc about my seroma while in her office after I had a ct at the hospital she looked and felt several very large seroma. She tried to drain it with syringes with or getting a few drops out .bright yellow in color.she then used a tool to re-open my incision and put the syringe through their still no luck draining it even with pushing on my tummy. She said it's behind my large amount of scar tissue on my lower belly and wraps around to my right side. She says my body will take care of it.