question: I have been diagnosed with S1 nerve sheath cysts . One on each side anterior to the spine . I went for a fine needle aspiration with ct and biopsy two weeks ago. They were unable, after many attempts and punctures of the cysts to pull any fluid. Not even enough for a biopsy. I am now told by neurosurgeon that he still believes these are cysts and another biopsy is not necessary. That we are going to leave them be. I have never heard of a cyst with no fluid. Two nurses did tell me they are not fluid filled and may be tumors. I m just confused. Please help. Should I worry? Should I push for another biopsy, and if so what type?