welcome to health care magic..
first of all i will tell you one thing that lipoma
is a localised collection(tumor) of fat cellls,,which is freely movable,painless,very slow growing,,soft to touch..it may occur any where in the body..
FNAC(fine needle aspiration cytology) is more reliable than ultrasound
....if FNAC report shows it is lipoma containing fat,,then there is no doubt that ti is lipoma,,your ultrasound report saying that lymphnode is totally wrong..
FNAC is 100%sure,,no need to undergo excisional biopsy
....if you are trouble some with that lipoma on the back of neck that is for cosmetic purposes,,consult general surgeon
and he/she will remove lipoma..dont be panic for surgery,,its just a ten min procedure with local anesthesia
and you may go home with out any problem...
hope you will understand my suggestion...
once again i am telling that there is no need for excision biopsy,..
thank you sir