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ICD-10-CM 2027 diagnosis code

M35.4Diffuse (eosinophilic) fasciitis

✓ Billable / specific

M35.4 is a valid, billable ICD-10-CM code for diffuse (eosinophilic) fasciitis. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M35.4

M35.4 is the ICD-10-CM diagnosis code for diffuse (eosinophilic) fasciitis. It belongs to category M35 (other systemic involvement of connective tissue), block M30-M36 (systemic connective tissue disorders) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within M35 (other systemic involvement of connective tissue), M35.4 is specifically for diffuse (eosinophilic) fasciitis. Related codes cover Sjogren syndrome (M35.0), other overlap syndromes (M35.1), Behcet's disease (M35.2), polymyalgia rheumatica (M35.3), multifocal fibrosclerosis (M35.5), relapsing panniculitis [Weber-Christian] (M35.6), hypermobility syndrome (M35.7), other specified systemic involvement of connective tissue (M35.8) and 1 more.

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 557 (Tendonitis, Myositis and Bursitis with MCC, relative weight 1.489) and DRG 558 (Tendonitis, Myositis and Bursitis without MCC, relative weight 0.8875), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), 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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 728.89 (other disorders of muscle, ligament, and fascia).

Notes that apply from higher levels

Instructions written at a parent level also apply to M35.4.

› From M35 Other systemic involvement of connective tissue
Excludes1
  • reactive perforating collagenosis (L87.1)

Broader instructions also apply from M30-M36 Systemic connective tissue disorders and Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to M35.4.

Codes whose notes reference M35.4

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 08 · Diseases and Disorders of the Musculoskeletal System and Connective Tissue

ICD-9-CM equivalent

Converter →
  • 728.89Other disorders of muscle, ligament, and fasciaapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

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
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M35.4

Is M35.4 billable?

Yes. M35.4 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M35.4 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M35.4 as a principal diagnosis.

Is M35.4 a CC or MCC?

No. M35.4 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M35.4 group to?

M35.4 is used in the MS-DRG v44.0 logic for MS-DRG 557 (Tendonitis, Myositis and Bursitis with MCC) and MS-DRG 558 (Tendonitis, Myositis and Bursitis without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for M35.4?

The CMS General Equivalence Mappings map M35.4 to ICD-9-CM 728.89.