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ICD-10-CM 2027 diagnosis code

C96.5Multifocal and unisystemic Langerhans-cell histiocytosis

✓ Billable / specificCC — complication/comorbidity

C96.5 is a valid, billable ICD-10-CM code for multifocal and unisystemic langerhans-cell histiocytosis. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Schüller-Christian disease or syndrome, ICD-10 code for Hand-Schüller-Christian disease or syndrome.

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 C96.5

C96.5 is the ICD-10-CM diagnosis code for multifocal and unisystemic Langerhans-cell histiocytosis. It belongs to category C96 (other and unspecified malignant neoplasms of lymphoid, hematopoietic and related tissue), block C81-C96 (malignant neoplasms of lymphoid, hematopoietic and related tissue) 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 C96 (other and unspecified malignant neoplasms of lymphoid, hematopoietic and related tissue), C96.5 is specifically for multifocal and unisystemic Langerhans-cell histiocytosis. Related codes cover multifocal and multisystemic (disseminated) Langerhans-cell histiocytosis (C96.0), malignant mast cell neoplasm (C96.2), sarcoma of dendritic cells (accessory cells) (C96.4), Unifocal Langerhans-cell histiocytosis (C96.6), malignant neoplasm of lymphoid, hematopoietic and related tissue, unspecified (C96.9), histiocytic sarcoma (C96.A) and other specified malignant neoplasms of lymphoid, hematopoietic and related tissue (C96.Z).

Don't report C96.5 together with the conditions in its Excludes1 note: multifocal and multisystemic (disseminated) Langerhans-cell histiocytosis (C96.0) and unifocal Langerhans-cell histiocytosis (C96.6).

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 642 (Inborn and Other Disorders of Metabolism, relative weight 1.3219), in MDC 10 (Endocrine, Nutritional and Metabolic Diseases and Disorders), 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 277.89 (other specified disorders of metabolism).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Hand-Schüller-Christian disease
  • Histiocytosis X, multifocal
Excludes1Not coded here — never report together with this code
  • multifocal and multisystemic (disseminated) Langerhans-cell histiocytosis (C96.0)
  • unifocal Langerhans-cell histiocytosis (C96.6)

Notes that apply from higher levels

Instructions written at a parent level also apply to C96.5.

› From C96 Other and unspecified malignant neoplasms of lymphoid, hematopoietic and related tissue
Excludes1
  • personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues (Z85.79)

Broader instructions also apply from C81-C96 Malignant neoplasms of lymphoid, hematopoietic and related tissue and Chapter 2: Neoplasms.

Alphabetic index entries

6 entries

Terms in the official ICD-10-CM index that lead to C96.5.

Codes whose notes reference C96.5

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 10 · Endocrine, Nutritional and Metabolic Diseases and Disorders

ICD-9-CM equivalent

Converter →
  • 277.89Other specified disorders of metabolismapproximate

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 C96.5

Is C96.5 billable?

Yes. C96.5 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can C96.5 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict C96.5 as a principal diagnosis.

Is C96.5 a CC or MCC?

C96.5 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does C96.5 group to?

C96.5 is used in the MS-DRG v44.0 logic for MS-DRG 642 (Inborn and Other Disorders of Metabolism). 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 C96.5?

The CMS General Equivalence Mappings map C96.5 to ICD-9-CM 277.89.