"Question ID","Question","Discussion","Answer","Year" "20061068","Primary Site--Unknown & ill-defined site: Should the primary site be coded to C809 [Unknown primary site] or C761 [Thorax, NOS] if the patient died following a limited work-up that included on a cytology on pericardial fluid that was positive for poor differentiated adenocarcinoma?","","Based on the information provided, code the primary site to C809 [Unknown primary site]. There is not enough information provided to suggest that the primary site is the thorax or any other location.","2006"