October 1 update. Our PDGM and ICD-10 tools now use the FY2027 code set: 190 codes added, 30 deleted, and no existing code changed clinical group.

See what changed

ICD-10 · PDGM grouping

C06 Malignant neoplasm of other and unspecified parts of mouth

All 6 codes in the C06 family, with the PDGM clinical group, comorbidity subgroup and primary-position rule CMS assigns, read from the CMS grouper crosswalk v07.2.26 and the CDC FY2027 code file.

ICD-10-CM FY2027 · CMS grouper v07.2.26

Codes in family

6

Can lead a claim

5

Cannot lead a claim

1

What CMS assigns to C06

5 of the 6 codes group to MMTA - Infectious Disease, Neoplasms, and Blood-Forming Diseases; 1 is assigned no clinical group. All 6 count toward the Malignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers comorbidity subgroup. 5 of the 6 can lead a claim.

  • Malignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers

Every code in C06

Descriptions are CDC’s FY2027 wording; where CMS’s grouper abbreviates one, its form is shown beneath.

CodeDescriptionPrimary positionClinical groupComorbidity subgroup
C06.0Malignant neoplasm of cheek mucosaCan lead a claimKMalignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers
C06.1Malignant neoplasm of vestibule of mouthCan lead a claimKMalignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers
C06.2Malignant neoplasm of retromolar areaCan lead a claimKMalignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers
C06.8 Malignant neoplasm of overlapping sites of other and unspecified parts of mouth
C06.80Malignant neoplasm of overlapping sites of unspecified parts of mouthCMS: Malignant neoplasm of ovrlp sites of unsp parts of mouthCan lead a claimKMalignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers
C06.89Malignant neoplasm of overlapping sites of other parts of mouthCMS: Malignant neoplasm of overlapping sites of oth prt mouthCan lead a claimKMalignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers
C06.9Malignant neoplasm of mouth, unspecifiedCannot lead a claimPrincipal diagnosis not assigned to a clinical groupNoneMalignant neoplasm of Lip, Oral cavity and Pharynx, includes Head and Neck Cancers

Sources: CMS HH PPS Grouper Software v07.2.26, effective 2026-10-01, for the clinical group, comorbidity subgroup, code-first conventions and primary-position flags; CDC NCHS ICD-10-CM FY2027 code descriptions for the family title and code wording. This is the crosswalk Medicare runs a claim through. Grouping also depends on admission source, timing, the OASIS functional items and the rest of the diagnosis list.

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