FY2027 ICD-10-CM reference
C37: Malignant neoplasm of thymus
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Malignant neoplasm of thymus. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Billable code. Verified against the official FY2027 order file.
Oct to Dec 2026, PY2027
CMS-HCC V28
Mapped- HCC 21Lymphoma and Other CancersCoefficient 0.671 (CNA, PY2027)
CMS-HCC V24
Not used by CMSESRD
Mapped- HCC 11Colorectal/Bladder/and Other CancersCoefficient 0.059 (Dialysis CE, PY2027)
RxHCC
Mapped- HCC 22Prostate, Breast, Bladder, and Other Cancers ...Coefficient 0.152 (MA-PD CE non-low aged, PY2027)
PACE (CMS-HCC V22 component)
Mapped- HCC 11Colorectal/Bladder/and Other Cancers
PACE ESRD (ESRD V21 component)
Mapped- HCC 11Colorectal/Bladder/and Other Cancers
PACE RxHCC (2018/2019 component)
Mapped- HCC 22Prostate, Breast, Bladder, and Other Cancers ...
Jan to Sep 2027, PY2028
CMS-HCC V28
Not published by CMSCMS-HCC V24
Not published by CMSESRD
Not published by CMSRxHCC
Not published by CMSPACE (CMS-HCC V22 component)
Not published by CMSPACE ESRD (ESRD V21 component)
Not published by CMSPACE RxHCC component
Not published by CMSOct to Dec 2026, BY2026
HHS-HCC
PendingJan to Sep 2027, BY2027
HHS-HCC
Not published by CMSFY2027 Tabular instructions
Instructions below include applicable chapter, section and parent-code notes. Each note identifies where it appears in the official source.
Instructional note
Functional activity
Source: C00-D49 (chapter, inherited).
Instructional note
All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
Source: C00-D49 (chapter, inherited).
Instructional note
Morphology [Histology]
Source: C00-D49 (chapter, inherited).
Instructional note
Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
Source: C00-D49 (chapter, inherited).
Instructional note
Primary malignant neoplasms overlapping site boundaries
Source: C00-D49 (chapter, inherited).
Instructional note
A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
Source: C00-D49 (chapter, inherited).
Instructional note
Malignant neoplasm of ectopic tissue
Source: C00-D49 (chapter, inherited).
Instructional note
Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
Source: C00-D49 (chapter, inherited).
Includes
malignant neoplasm of middle ear
Source: C30-C39 (section, inherited).
Excludes1
mesothelioma (C45.-)
Source: C30-C39 (section, inherited).
Excludes1
malignant carcinoid tumor of the thymus (C7A.091)
Source: C37 (category, direct).
Compare the FY2027 additions, removals and billable-status changes
What does C37 mean in FY2027?
The official ICD-10-CM descriptor is Malignant neoplasm of thymus. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is C37 billable in FY2027?
The FY2027 order file marks C37 as billable. Check the complete Tabular instructions and documentation before assigning it.
Does C37 map to an HCC?
Oct to Dec 2026, PY2027: CMS-HCC V28 HCC 21 (Lymphoma and Other Cancers); CMS-HCC V24: Not used by CMS; ESRD HCC 11 (Colorectal/Bladder/and Other Cancers); RxHCC HCC 22 (Prostate, Breast, Bladder, and Other Cancers and Tumors). Jan to Sep 2027, PY2028: CMS-HCC V28: Not published by CMS; CMS-HCC V24: Not published by CMS; ESRD: Not published by CMS; RxHCC: Not published by CMS. Oct to Dec 2026, BY2026: HHS-HCC: Pending. Jan to Sep 2027, BY2027: HHS-HCC: Not published by CMS. Base coefficients are reference values, not a member total.
Source: CMS FY2027 ICD-10-CM order file. Payment model: CMS CY 2027 Rate Announcement. Read the FY2027 Official Guidelines.
Review the FY2026 April edition