ICD-10-CM 2027 diagnosis code
D33.9Benign neoplasm of central nervous system, unspecified
D33.9 is a valid, billable ICD-10-CM code for benign neoplasm of central nervous system, unspecified. 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 D33.9
D33.9 is the ICD-10-CM diagnosis code for benign neoplasm of central nervous system, unspecified. It belongs to category D33 (benign neoplasm of brain and other parts of central nervous system), block D10-D36 (benign neoplasms, except benign neuroendocrine tumors) 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 D33, choose D33.9 (central nervous system, unspecified) only when documentation doesn't support a more specific option: brain, supratentorial (D33.0), brain, infratentorial (D33.1), brain, unspecified (D33.2), cranial nerves (D33.3), spinal cord (D33.4) and other specified parts of central nervous system (D33.7).
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 054 (Nervous System Neoplasms with MCC, relative weight 1.5194) and DRG 055 (Nervous System Neoplasms without MCC, relative weight 1.0296), in MDC 01 (Diseases and Disorders of the Nervous 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 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 225.9 (benign neoplasm of nervous system, part unspecified).
Coding notes
- Benign neoplasm of nervous system (central) NOS
Notes that apply from higher levels
Instructions written at a parent level also apply to D33.9.
Broader instructions also apply from Chapter 2: Neoplasms.
Table of Drugs & Neoplasms entries
- Neoplasm, neoplastic › epidural — Benign
- Neoplasm, neoplastic › extradural — Benign
- Neoplasm, neoplastic › motor tract — Benign
- Neoplasm, neoplastic › nervous system (central) — Benign
- Neoplasm, neoplastic › parasellar — Benign
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 01 · Diseases and Disorders of the Nervous System
ICD-9-CM equivalent
Converter →- 225.9Benign neoplasm of nervous system, part unspecifiedapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about D33.9
Is D33.9 billable?
- Yes. D33.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can D33.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict D33.9 as a principal diagnosis.
Is D33.9 a CC or MCC?
- No. D33.9 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does D33.9 group to?
- D33.9 is used in the MS-DRG v44.0 logic for MS-DRG 054 (Nervous System Neoplasms with MCC) and MS-DRG 055 (Nervous System Neoplasms 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 D33.9?
- The CMS General Equivalence Mappings map D33.9 to ICD-9-CM 225.9.