Guidelines for cancers for which primary site is unknown.

§ 81.23 Guidelines for cancers for which primary site is unknown. (a) In claims for which the primary cancer site cannot be determined, but a site of metastasis is known, DOL will calculate probability of causation estimates for various likely primary sites. Table 1 of this paragraph (a) indicates the primary cancer site(s) DOL will use in NIOSH–IREP when the primary cancer site is unknown. Table 1 to Paragraph (a) Primary cancers (ICD–10–CM codes) for which probability of causation is to be calculated, if only a secondary cancer site is known. “M” indicates cancer site should be used for males only, and “F” indicates the cancer site should be used for females only. Secondary cancer (ICD–10–CM code) ICD–10–CM code of likely primary cancers Lymph nodes of head, face and neck (C77.0) C01, C02, C07(M), C08(M), C09(M), C10(M), C14(F), C32(M), C33, C34, C43, C44, C50(F), C73(F), D03. Intrathoracic lymph nodes (C77.1) C15(M), C33, C34, C50(F). Intra-abdominal lymph nodes (C77.2) C15(M), C16(M), C18, C25(F), C33, C34, C50(F), C53(F), C61(M), C64, C65, C66, C68, C82(F), C84(F) (excluding C84.6, C84.7), C85(F), C86(F) (excluding C86.5, C86.6), C91.4(F), C96(F). Lymph nodes of axilla and upper limb (C77.3) C33, C34, C43, C50(F) , D03. Inguinal and lower limb lymph nodes (C77.4) C19(M), C20(M), C21(M), C33, C34, C43, C44(F), C60(M), C63(M), D03. Intrapelvic lymph nodes (C77.5) C18(M), C19(F), C20(F), C21(F), C33(M), C34(M), C53(F), C54(F), C61(M), C67. Lymph nodes of multiple sites (C77.8) C15(M), C16(M), C18(M), C33, C34, C50(F). Lymph nodes, site unspecified (C77.9) C15(M), C16, C18, C33, C34, C43, C50(F), C61(M), D03. Lung (C78.0) C18, C33, C34, C43(M), C50(F), C61(M), C67(M), C64, C65, C66, C68, D03(M). Mediastinum (C78.1) C15(M), C33, C34, C50(F). Pleura (C78.2) C15(M), C18(M), C33, C34, C50(F), C56(F), C57(F), C61(M), C64(M), C65(M), C66(M), C68(M). Other respiratory organs (C78.3) C15, C18(M), C32, C33, C34, C44(M), C50(F), C61(M), C73(F). Small intestine, including duodenum (C78.4) C17, C18, C25, C33, C34, C49, C43(M), C50(F), C56(F), C57(F), C64(M), C65(M), C66(M), C68(M), D03(M). Large intestine and rectum (C78.5) C18, C19, C20, C21, C33, C34, C50(F), C56(F), C57(F), C61(M). Retroperitoneum and peritoneum (C78.6) C16, C18, C19(M), C20(M), C21(M), C25, C33(M), C34(M), C49, C50(F), C54(F), C56(F), C57(F). Liver, specified as secondary (C78.7) C16(M), C18, C19(M), C20(M), C21(M), C25, C33, C34, C50(F). Other digestive organs (C78.8) C15(M), C16, C18, C25, C33, C34, C50(F), C61(M). Kidney (C79.0) C18, C33, C34, C50(F), C53(F), C61(M), C67, C64, C65, C66, C68, C82(F), C84(F) (excluding C84.6, C84.7), C85(F), C86(F) (excluding C86.5, C86.6), C91.4(F), C96(F). Other urinary organs (C79.1) C18, C50(F), C53(F), C56(F), C57(F), C61(M), C67, C64(F), C65(F), C66(F), C68(F). Skin (C79.2) C18, C33, C34, C49(M), C43, C44(M), C50(F), C64(M), C65(M), C66(M), C68(M), D03. Brain and spinal cord (C79.3) C33, C34, C43(M), C50(F), D03(M). Other parts of nervous system (C79.4) C33, C34, C43(M), C50(F), C61(M), C82, C84 (excluding C84.6, C84.7), C85, C86 (excluding C86.5, C86.6), C91.4, C96, D03(M). Bone and bone marrow (C79.5) C33, C34, C50(F), C61(M). Ovary (C79.6) C18(F), C50(F), C56(F), C57(F). Adrenal gland (C79.7) C18(F), C33, C34, C50(F). Other specified sites (C79.8) C18, C33, C34, C43(M), C50(F), C56(F), C57(F), C61(M), C67(M), D03(M). Unspecified sites (C79.9) C18, C33, C34, C43(M), C50(F), C56(F), C57(F), C61(M), C67(M), D03(M). Carcinoid tumor of distant lymph nodes (C7B.01) C15(M), C16, C18, C33, C34, C43, C50(F),C61(M), D03. Carcinoid tumor of liver (C7B.02) C16(M), C18, C19(M), C20(M), C21(M), C25, C33, C34, C50(F). Carcinoid tumor of bone (C7B.03) C33, C34, C50(F), C61(M). Carcinoid tumor of peritoneum (C7B.04) C16, C18, C19(M), C20(M), C21(M), C25, C33(M), C34(M), C49, C50(F), C54(F), C56(F), C57(F). Merkel cell carcinoma (C7B.1) C18, C33, C34, C49(M), C43, C44(M), C50(F), C64(M), C65(M), C66(M), C68(M), D03. (b) DOL will select the site producing the highest estimate for probability of causation to adjudicate the claim. [67 FR 22309, May 2, 2002, as amended at 84 FR 37590, Aug. 1, 2019]