2027 ICD-10-CM Diagnosis Code C71.7Malignant neoplasm of brain stem
ICD-10-CM Codes›C00–D49›C69-C72›C71
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 20
- Chronic Condition
C71.7 is a billable ICD-10-CM diagnosis code for malignant neoplasm of brain stem. 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. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 40 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system cancers - brain.
For Medicare Advantage risk adjustment, C71.7 maps to CMS-HCC Category 20 (Lung and Other Severe Cancers) under the V28 model, adding a risk factor of about 1.136 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C71.7 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.
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.
- Astrocytoma of brain stem
- Diffuse intrinsic pontine glioma
- Ependymoma of brain stem
- Glioma of brainstem
- Low grade glioma of brainstem
- Malignant glioma of brainstem
- Malignant neoplasm of brainstem
- Malignant neoplasm of cerebral peduncle
- Malignant neoplasm of medulla oblongata
- Malignant neoplasm of midbrain
- Malignant neoplasm of pons
- Oligodendroglioma of brain
- Oligodendroglioma of brain stem
- Primary astrocytoma of brain stem
- Primary diffuse intrinsic pontine glioma
- Primary glioblastoma multiforme of brain
- Primary glioblastoma multiforme of brainstem
- Primary malignant astrocytoma of brain
- Primary malignant glioma of brainstem
- Primary malignant neoplasm of brain stem
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C71.7: its own notes plus those printed at C71 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Malignant neoplasm of fourth cerebral ventricle
- Infratentorial malignant neoplasm NOS
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Notes
General instructions on how these codes are used.
- 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 C71.7, its category, or a range that includes it.
Applicable To 2
These notes mention C71.7.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Malignant Brain Stem Neoplasm
a primary or metastatic malignant neoplasm that affects the brain stem.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| basis pedunculi | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › choroid plexus | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › medulla oblongata | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › midbrain | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › peduncle | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › pons | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › stem | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| brain NEC › ventricle (floor) › fourth | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| cerebrum, cerebral (cortex) (hemisphere) (white matter) › peduncle | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| cerebrum, cerebral (cortex) (hemisphere) (white matter) › ventricle › fourth | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| ependyma (brain) › fourth ventricle | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| medulla › oblongata | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| midbrain | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| olive (brain) | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| peduncle, cerebral | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| pons (varolii) | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| pyramid (brain) | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| spine, spinal (column) › bulb | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| stem, brain | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
| ventricle (cerebral) (floor) (lateral) (third) › fourth | C71.7 | C79.31 | – | D33.1 | D43.1 | D49.6 |
Patient EducationClinical
Brain Tumors
A brain tumor is a growth of abnormal cells in the tissues of the brain. Brain tumors can be benign, with no cancer cells, or malignant, with cancer cells that grow quickly. Some are primary brain tumors, which start in the brain. Others are metastatic, and they start somewhere else in the body and move to the brain.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C71.7 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C71.7Overview
What is the ICD-10 code for malignant neoplasm of brain stem?
The ICD-10-CM code for malignant neoplasm of brain stem is C71.7 (sometimes written as C717). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C71.7 (Malignant neoplasm of brain) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of brain stem on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C71.7 group to?
When malignant neoplasm of brain stem 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.
Is C71.7 a CC or MCC?
CMS lists C71.7 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 40 closely related codes in its exclusion list.
Can C71.7 be reported with a code from C69.6?
Not as a rule. The Excludes1 note at C71, which applies to C71.7, lists "retrobulbar malignant neoplasm (C69.6-)". 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 HCC is C71.7?
C71.7 (malignant neoplasm of brain stem) maps to CMS-HCC Category 20 (Lung and Other Severe Cancers), commonly written as HCC 20, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 10 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 C71.7 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C71.7 adds a risk adjustment factor of about 1.136 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.672 to 1.214 depending on the payment segment). A more severe related category (HCC 17, HCC 18, and HCC 19) supersedes it when both are reported. See the full factor table on the HCC 20 category page.
