Skip to content
Dx

ICD-10-CM 2027 diagnosis code

C96.20Malignant mast cell neoplasm, unspecified

✓ Billable / specificCC — complication/comorbidity

C96.20 is a valid, billable ICD-10-CM code for malignant mast cell neoplasm, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code last changed in FY2018 (effective October 1, 2017). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About C96.20

C96.20 is the ICD-10-CM diagnosis code for malignant mast cell neoplasm, unspecified. 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 C96.2, choose C96.20 (unspecified) only when documentation doesn't support a more specific option: aggressive systemic mastocytosis (C96.21), mast cell sarcoma (C96.22) and other malignant mast cell neoplasm (C96.29).

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 011 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with MCC, relative weight 5.6154), DRG 012 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with CC, relative weight 4.381), DRG 013 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy without CC/MCC, relative weight 2.7307), DRG 820 (Lymphoma and Leukemia with Major O.R. Procedures with MCC, relative weight 6.2481), DRG 821 (Lymphoma and Leukemia with Major O.R. Procedures with CC, relative weight 2.2023), DRG 822 (Lymphoma and Leukemia with Major O.R. Procedures without CC/MCC, relative weight 1.1272) and 6 more, in Pre-MDC and MDC 17 (Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms), 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 FY2018, effective October 1, 2017.

Before ICD-10, this condition was coded in ICD-9-CM as 202.60 (malignant mast cell tumors, unspecified site, extranodal and solid organ sites), 202.61 (malignant mast cell tumors, lymph nodes of head, face, and neck), 202.62 (malignant mast cell tumors, intrathoracic lymph nodes) and 6 more.

Notes that apply from higher levels

Instructions written at a parent level also apply to C96.20.

› From C96.2 Malignant mast cell neoplasm
Excludes1
  • indolent mastocytosis (D47.02)
  • mast cell leukemia (C94.30)
  • mastocytosis (congenital) (cutaneous) (Q82.2)
› 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

2 entries

Terms in the official ICD-10-CM index that lead to C96.20.

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.

ICD-9-CM equivalent

Converter →
  • 202.60Malignant mast cell tumors, unspecified site, extranodal and solid organ sitesapproximate
  • 202.61Malignant mast cell tumors, lymph nodes of head, face, and neckapproximate
  • 202.62Malignant mast cell tumors, intrathoracic lymph nodesapproximate
  • 202.63Malignant mast cell tumors, intra-abdominal lymph nodesapproximate
  • 202.64Malignant mast cell tumors, lymph nodes of axilla and upper limbapproximate
  • 202.65Malignant mast cell tumors, lymph nodes of inguinal region and lower limbapproximate
  • 202.66Malignant mast cell tumors, intrapelvic lymph nodesapproximate
  • 202.67Malignant mast cell tumors, spleenapproximate
  • 202.68Malignant mast cell tumors, lymph nodes of multiple sitesapproximate

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
  • FY2018 (effective 10/1/2017): Added
  • No changes since FY2018.

Common questions about C96.20

Is C96.20 billable?

Yes. C96.20 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can C96.20 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict C96.20 as a principal diagnosis.

Is C96.20 a CC or MCC?

C96.20 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does C96.20 group to?

C96.20 is used in the MS-DRG v44.0 logic for MS-DRG 011 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with MCC), MS-DRG 012 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with CC), MS-DRG 013 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy without CC/MCC), MS-DRG 820 (Lymphoma and Leukemia with Major O.R. Procedures with MCC), MS-DRG 821 (Lymphoma and Leukemia with Major O.R. Procedures with CC), MS-DRG 822 (Lymphoma and Leukemia with Major O.R. Procedures without CC/MCC) and 6 more. 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 C96.20?

The CMS General Equivalence Mappings map C96.20 to ICD-9-CM 202.60, 202.61, 202.62, 202.63 and 5 more.