Why might it be that i need a biopsy of neck lymph nodes?

Rule out malignancy.: The need for a biopsy depends upon a patient's specific clinical situation. If a healthcare provider has suggested a tissue biopsy, it is likely because the diagnosis is uncertain. A biopsy would allow for the tissues to be studied under the microscope. This could help establish if the condition is an infection or a tumor and if a tumor is benign or malignant. Talk with your doctor.