Nerve seath tumor in the thigh near knee

He has it from last 4 years but in last two weeks it has become painful, no issue in norm activities but he is having pain in thigh for few minutes at randomn times USG Report Summary A well-defined, encapsulated lesion is present in the posteromedial thigh near the knee, affecting the saphenous nerve. It is likely a peripheral nerve sheath tumor, with schwannoma or neurofibroma being possible diagnoses. There is also a PCL sprain with laxity in the knee. No signs of fracture, marrow edema, joint effusion, or Baker’s cyst. AIIMS Raipur doctors suggested -FNAC of swelling -NCS and EMG of right lower limb, Refer to Neurologist Please suggest, should we do FNAC or Biopsy as one Manipal doctor suggested What things I should do here, who is better specialist to treat this?