Cumulative Official WHO Updates to ICD 10 - 1996 - 2001

E. Primary site unknown. If the statement, “primary site unknown”, or its equivalent, appears anywhere on a certificate, code to the category for unspecified site for the morphological type involved (e.g. adenocarcinoma C80, fibrosarcoma C49.9, osteosarcoma C41.9), regardless of the site(s) mentioned elsewhere on the certificate. ................
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