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ICD-10-CM 2027 diagnosis code

C78.31Secondary malignant neoplasm of larynx

✓ Billable / specificNew for 2027CC — complication/comorbidity

C78.31 is a valid, billable ICD-10-CM code for secondary malignant neoplasm of larynx. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS, effective October 1, 2026. Updated September 29, 2026. About our data

About C78.31

C78.31 is the ICD-10-CM diagnosis code for secondary malignant neoplasm of larynx. It belongs to category C78 (secondary malignant neoplasm of respiratory and digestive organs), block C76-C80 (malignant neoplasms of ill-defined, other secondary and unspecified sites) and chapter 2 (neoplasms). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within C78.3 (secondary malignant neoplasm of other and unspecified respiratory organs), C78.31 is specifically for secondary malignant neoplasm of larynx. Related codes cover unspecified respiratory organ (C78.30), pharynx (C78.32) and other respiratory organs (C78.39).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 180 (Respiratory Neoplasms with MCC, relative weight 1.7806), DRG 181 (Respiratory Neoplasms with CC, relative weight 1.0936) and DRG 182 (Respiratory Neoplasms without CC/MCC, relative weight 0.7439), in MDC 04 (Diseases and Disorders of the Respiratory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It was added in FY2027, effective October 1, 2026.

Notes that apply from higher levels

Instructions written at a parent level also apply to C78.31.

› From C78 Secondary malignant neoplasm of respiratory and digestive organs
Excludes1
  • secondary carcinoid tumors of liver (C7B.02)
  • secondary carcinoid tumors of peritoneum (C7B.04)
Excludes2
  • lymph node metastases (C77.0)

Broader instructions also apply from Chapter 2: Neoplasms.

Table of Drugs & Neoplasms entries

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2027 (effective 10/1/2026): Added

Common questions about C78.31

Is C78.31 billable?

Yes. C78.31 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can C78.31 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict C78.31 as a principal diagnosis.

Is C78.31 a CC or MCC?

C78.31 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does C78.31 group to?

C78.31 is used in the MS-DRG v44.0 logic for MS-DRG 180 (Respiratory Neoplasms with MCC), MS-DRG 181 (Respiratory Neoplasms with CC) and MS-DRG 182 (Respiratory Neoplasms without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

Did C78.31 change for 2027?

Yes. For FY2027 (effective October 1, 2026) it was added to the code set.