I,am looking for pictures (if any) of pnvs. My daughter in law has currently acquired a LARGER knot behind her knee. It is not a cyst, tumor, not sure (dr.s say). They have biosied this knot.... however, just wondering what could cause this larger knot. It hurts like hell, she cannot bend her leg ...... any guess???? YYYY@YYYY . PLUS she is a nurse practitioner and she does not know, doctors do not know......so,we are ALLL in the dark