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ICD-10-CM 2027 diagnosis code

C4A.112Merkel cell carcinoma of right lower eyelid, including canthus

✓ Billable / specific

C4A.112 is a valid, billable ICD-10-CM code for merkel cell carcinoma of right lower eyelid, including canthus. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Merkel cell carcinoma of right lower eyelid, inc canthus

Code last changed in FY2019 (effective October 1, 2018). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About C4A.112

C4A.112 is the ICD-10-CM diagnosis code for Merkel cell carcinoma of right lower eyelid, including canthus. It belongs to category C4A (Merkel cell carcinoma), block C43-C44 (melanoma and other malignant neoplasms of skin) 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 C4A.11 (Merkel cell carcinoma of right eyelid, including canthus), C4A.112 is specifically for Merkel cell carcinoma of right lower eyelid, including canthus. Related codes cover upper eyelid, including canthus (C4A.111).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 595 (Major Skin Disorders with MCC, relative weight 2.0239) and DRG 596 (Major Skin Disorders without MCC, relative weight 1.1071), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), 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 FY2019, effective October 1, 2018.

Notes that apply from higher levels

Instructions written at a parent level also apply to C4A.112.

Broader instructions also apply from Chapter 2: Neoplasms.

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.

MDC 09 · Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast

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
  • FY2019 (effective 10/1/2018): Added
  • No changes since FY2019.

Common questions about C4A.112

Is C4A.112 billable?

Yes. C4A.112 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can C4A.112 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict C4A.112 as a principal diagnosis.

Is C4A.112 a CC or MCC?

No. C4A.112 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does C4A.112 group to?

C4A.112 is used in the MS-DRG v44.0 logic for MS-DRG 595 (Major Skin Disorders with MCC) and MS-DRG 596 (Major Skin Disorders without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.