2027 ICD-10-CM Diagnosis Code D49.6Neoplasm of unspecified behavior of brain

ICD-10-CM Codes›C00–D49›D49›D49

ICD-10-CM D49.6
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

D49.6 is a billable ICD-10-CM diagnosis code for neoplasm of unspecified behavior of brain. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 54 through 55. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neoplasms of unspecified nature or uncertain behavior.

For Medicare Advantage risk adjustment, D49.6 maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors) under the V28 model, adding a risk factor of about 0.186 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
D49.6
Billable Status
Yes — Valid for Submission
Code Describes
Neoplasm of unspecified behavior of brain
Short Description
Neoplasm of unspecified behavior of brain
Same as the full description in the CMS dataset.
Parent Code
D49
Neoplasms of unspecified behavior

Code Classification

ChapterC00–D49Neoplasms
SectionD49Neoplasms of unspecified behavior
CategoryD49Neoplasms of unspecified behavior
This CodeD49.6Neoplasm of unspecified behavior of brain

Medicare Risk Adjustment (HCC)Billing

D49.6 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 23— Prostate, Breast, and Other Cancers and Tumors
Payment HCC · PY 2027 one of 234 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.186
community, non-dual, aged · ranges 0.186–0.237 across segments
Hierarchy
Superseded by HCC 17, HCC 18, HCC 19, HCC 20, HCC 21, and HCC 22
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 12
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 12 · ESRD (V21): HCC 12 · ESRD (V24): HCC 12
ESRD V21 weights: 0.046 dialysis, 0.156–0.194 functioning graft · ESRD V24 weights: 0.045 dialysis, 0.162–0.219 functioning graft
Part D (RxHCC)
RxHCC 22 — Prostate, Breast, Bladder, and Other Cancers and Tumors
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cerebellopontine angle neoplasm
  • Cerebral degeneration due to neoplastic disease
  • Epilepsy due to intracranial neoplasm
  • Germ cell neoplasm of brain
  • Headache due to intracranial neoplasm
  • Hemichorea
  • Hemichorea due to neoplasm of brain
  • Hydrocephalus due to intracranial neoplasm
  • Intracranial neoplasm
  • Neoplasm of brain
  • Neoplasm of brain stem
  • Neoplasm of cerebellum
  • Neoplasm of cerebrum
  • Neoplasm of choroid plexus
  • Neoplasm of frontal lobe
  • Neoplasm of hypothalamus
  • Neoplasm of occipital lobe
  • Neoplasm of parietal lobe
  • Neoplasm of temporal lobe
  • Neoplasm of ventricle of brain
  • Obstructive hydrocephalus
  • Pain due to neoplastic disease

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to D49.6: its own notes plus those printed at D49 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From D49 Neoplasms of unspecified behavior applies to 14 codes
  • 'growth' NOS
  • neoplasm NOS
  • new growth NOS
  • tumor NOS

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • neoplasm of unspecified behavior of cerebral meninges (D49.7)
  • neoplasm of unspecified behavior of cranial nerves (D49.7)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From D49 Neoplasms of unspecified behavior applies to 14 codes
  • neoplasms of uncertain behavior (D37-D44, D48)

Notes

General instructions on how these codes are used.

From D49 Neoplasms of unspecified behavior applies to 14 codes
  • Category D49 classifies by site neoplasms of unspecified morphology and behavior. The term 'mass', unless otherwise stated, is not to be regarded as a neoplastic growth.
From Chapter 2 (C00-D49) Neoplasms applies to 1,730 codes
  • Functional activity
  • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
  • Morphology [Histology]
  • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
  • Primary malignant neoplasms overlapping site boundaries
  • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
  • Malignant neoplasm of ectopic tissue
  • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name D49.6, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming D49.6: they are not reported together with it, unless the two conditions are unrelated.

  • Block D37-D48 Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes
    neoplasms of unspecified behavior (D49.-) names D49.-, which includes this code

Notes 1

These notes mention D49.6.

  • D49 Neoplasms of unspecified behavior
    Category D49 classifies by site neoplasms of unspecified morphology and behavior. The term 'mass', unless otherwise stated, is not to be regarded as a neoplastic growth. names D49, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO072
Neoplasms of unspecified nature or uncertain behavior
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Brain Neoplasm|Brain Tumor

    a benign or malignant neoplasm that arises from or metastasizes to the brain.

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
basal gangliaC71.0C79.31–D33.0D43.0D49.6
basis pedunculiC71.7C79.31–D33.1D43.1D49.6
brain NECC71.9C79.31–D33.2D43.2D49.6
brain NEC › basal gangliaC71.0C79.31–D33.0D43.0D49.6
brain NEC › cerebellopontine angleC71.6C79.31–D33.1D43.1D49.6
brain NEC › cerebellum NOSC71.6C79.31–D33.1D43.1D49.6
brain NEC › cerebrumC71.0C79.31–D33.0D43.0D49.6
brain NEC › choroid plexusC71.7C79.31–D33.1D43.1D49.6
brain NEC › corpus callosumC71.8C79.31–D33.2D43.2D49.6
brain NEC › corpus striatumC71.0C79.31–D33.0D43.0D49.6
brain NEC › cortex (cerebral)C71.0C79.31–D33.0D43.0D49.6
brain NEC › frontal lobeC71.1C79.31–D33.0D43.0D49.6
brain NEC › globus pallidusC71.0C79.31–D33.0D43.0D49.6
brain NEC › hippocampusC71.2C79.31–D33.0D43.0D49.6
brain NEC › hypothalamusC71.0C79.31–D33.0D43.0D49.6
brain NEC › internal capsuleC71.0C79.31–D33.0D43.0D49.6
brain NEC › medulla oblongataC71.7C79.31–D33.1D43.1D49.6
brain NEC › midbrainC71.7C79.31–D33.1D43.1D49.6
brain NEC › occipital lobeC71.4C79.31–D33.0D43.0D49.6
brain NEC › parietal lobeC71.3C79.31–D33.0D43.0D49.6
brain NEC › peduncleC71.7C79.31–D33.1D43.1D49.6
brain NEC › ponsC71.7C79.31–D33.1D43.1D49.6
brain NEC › stemC71.7C79.31–D33.1D43.1D49.6
brain NEC › tapetumC71.8C79.31–D33.2D43.2D49.6
brain NEC › temporal lobeC71.2C79.31–D33.0D43.0D49.6
brain NEC › thalamusC71.0C79.31–D33.0D43.0D49.6
brain NEC › uncusC71.2C79.31–D33.0D43.0D49.6
brain NEC › ventricle (floor)C71.5C79.31–D33.0D43.0D49.6
brain NEC › ventricle (floor) › fourthC71.7C79.31–D33.1D43.1D49.6
cerebellopontine (angle)C71.6C79.31–D33.1D43.1D49.6
cerebellum, cerebellarC71.6C79.31–D33.1D43.1D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter)C71.0C79.31–D33.0D43.0D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) › peduncleC71.7C79.31–D33.1D43.1D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) › ventricleC71.5C79.31–D33.0D43.0D49.6
cerebrum, cerebral (cortex) (hemisphere) (white matter) › ventricle › fourthC71.7C79.31–D33.1D43.1D49.6
choroid › plexusC71.5C79.31–D33.0D43.0D49.6
corpus › callosum, brainC71.0C79.31–D33.2D43.2D49.6
corpus › striatum, cerebrumC71.0C79.31–D33.0D43.0D49.6
cortex › cerebralC71.0C79.31–D33.0D43.0D49.6
cranial (fossa, any)C71.9C79.31–D33.2D43.2D49.6
ependyma (brain)C71.5C79.31–D33.0D43.0D49.6
ependyma (brain) › fourth ventricleC71.7C79.31–D33.1D43.1D49.6
fossa (of) › anterior (cranial)C71.9C79.31–D33.2D43.2D49.6
fossa (of) › cranialC71.9C79.31–D33.2D43.2D49.6
fossa (of) › middle (cranial)C71.9C79.31–D33.2D43.2D49.6
fossa (of) › posterior (cranial)C71.9C79.31–D33.2D43.2D49.6
frontal › lobe, brainC71.1C79.31–D33.0D43.0D49.6
frontal › poleC71.1C79.31–D33.0D43.0D49.6
ganglia [See Also: Neoplasm, nerve, peripheral] › basalC71.0C79.31–D33.0D43.0D49.6
globus pallidusC71.0C79.31–D33.0D43.0D49.6
hemisphere, cerebralC71.0C79.31–D33.0D43.0D49.6
hippocampus, brainC71.2C79.31–D33.0D43.0D49.6
hypothalamusC71.0C79.31–D33.0D43.0D49.6
insulaC71.0C79.31–D33.0D43.0D49.6
insular tissue (pancreas) › brainC71.0C79.31–D33.0D43.0D49.6
internal › capsuleC71.0C79.31–D33.0D43.0D49.6
intracranial NECC71.9C79.31–D33.2D43.2D49.6
island of ReilC71.0C79.31–D33.0D43.0D49.6
medulla › oblongataC71.7C79.31–D33.1D43.1D49.6
midbrainC71.7C79.31–D33.1D43.1D49.6
motor tract › brainC71.9C79.31–D33.2D43.2D49.6
occipital › lobe or pole, brainC71.4C79.31–D33.0D43.0D49.6
olive (brain)C71.7C79.31–D33.1D43.1D49.6
operculum (brain)C71.0C79.31–D33.0D43.0D49.6
palliumC71.0C79.31–D33.0D43.0D49.6
parietal › lobe, brainC71.3C79.31–D33.0D43.0D49.6
peduncle, cerebralC71.7C79.31–D33.1D43.1D49.6
plexus › choroidC71.5C79.31–D33.0D43.0D49.6
pole › frontalC71.1C79.31–D33.0D43.0D49.6
pole › occipitalC71.4C79.31–D33.0D43.0D49.6
pons (varolii)C71.7C79.31–D33.1D43.1D49.6
posterior fossa (cranial)C71.9C79.31–D33.2D43.2D49.6
putamenC71.0C79.31–D33.0D43.0D49.6
pyramid (brain)C71.7C79.31–D33.1D43.1D49.6
rhinencephalonC71.0C79.31–D33.0D43.0D49.6
spine, spinal (column) › bulbC71.7C79.31–D33.1D43.1D49.6
stem, brainC71.7C79.31–D33.1D43.1D49.6
suprasellar (region)C71.9C79.31–D33.2D43.2D49.6
supratentorial (brain) NECC71.0C79.31–D33.0D43.0D49.6
tapetum, brainC71.8C79.31–D33.2D43.2D49.6
temporal › lobe or poleC71.2C79.31–D33.0D43.0D49.6
thalamusC71.0C79.31–D33.0D43.0D49.6
uncus, brainC71.2C79.31–D33.0D43.0D49.6
ventricle (cerebral) (floor) (lateral) (third)C71.5C79.31–D33.0D43.0D49.6
ventricle (cerebral) (floor) (lateral) (third) › fourthC71.7C79.31–D33.1D43.1D49.6
vermis, cerebellumC71.6C79.31–D33.1D43.1D49.6
white matter (central) (cerebral)C71.0C79.31–D33.0D43.0D49.6

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert D49.6 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
239.6 Brain neoplasm NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About D49.6Overview

What is the ICD-10 code for neoplasm of unspecified behavior of brain?

The ICD-10-CM code for neoplasm of unspecified behavior of brain is D49.6 (sometimes written as D496). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is D49.6 (Neoplasms of unspecified behavior) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report neoplasm of unspecified behavior of brain on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does D49.6 group to?

When neoplasm of unspecified behavior of brain is the principal diagnosis on an inpatient stay, it groups to MS-DRG 55, 54, with relative weights from 1.0291 to 1.5197 depending on complications. Higher weights mean higher Medicare reimbursement.

Can D49.6 be reported with D49.7?

Not as a rule. The Excludes1 note on D49.6 lists "neoplasm of unspecified behavior of cerebral meninges (D49.7)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of D49.6?

Under the General Equivalence Mappings, neoplasm of unspecified behavior of brain converts to ICD-9-CM 239.6 (brain neoplasm NOS). The mapping is a direct match.

What HCC is D49.6?

D49.6 (neoplasm of unspecified behavior of brain) maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors), commonly written as HCC 23, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 12 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 22.

Does D49.6 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, D49.6 adds a risk adjustment factor of about 0.186 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.186 to 0.237 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, HCC 21, and HCC 22) supersedes it when both are reported. See the full factor table on the HCC 23 category page.