2027 ICD-10-CM Diagnosis Code C33Malignant neoplasm of trachea
ICD-10-CM Codes›C00–D49›C30-C39›C33
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 20
- Chronic Condition
C33 is a billable ICD-10-CM diagnosis code for malignant neoplasm of trachea. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 180 through 182. 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 46 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Respiratory cancers.
For Medicare Advantage risk adjustment, C33 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
C33 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.
- Acinar cell carcinoma of trachea
- Adenocarcinoma of trachea
- Adenoid cystic carcinoma of trachea
- Adenosquamous carcinoma of trachea
- Basaloid squamous cell carcinoma of trachea
- Clear cell adenocarcinoma of trachea
- Clear cell squamous cell carcinoma of trachea
- Giant cell carcinoma of trachea
- Lymphoepithelial carcinoma of trachea
- Malignant neoplasm of carina of trachea
- Malignant neoplasm of cartilage of trachea
- Malignant neoplasm of mucosa of trachea
- Malignant neoplasm of trachea
- Mucinous adenocarcinoma of trachea
- Mucinous cystadenocarcinoma of trachea
- Myoepithelial carcinoma
- Myoepithelial carcinoma of trachea
- Neoplasm of carina
- Neoplasm of lower respiratory tract and mediastinum
- Papillary adenocarcinoma of trachea
- Papillary squamous cell carcinoma of trachea
- Primary acantholytic squamous cell carcinoma
- Primary acinar cell carcinoma of trachea
- Primary adenocarcinoma of trachea
- Primary adenoid cystic carcinoma of trachea
- Primary adenosquamous carcinoma of trachea
- Primary adenosquamous cell carcinoma
- Primary basaloid squamous cell carcinoma of trachea
- Primary clear cell adenocarcinoma of trachea
- Primary clear cell squamous cell carcinoma of trachea
- Primary giant cell carcinoma of trachea
- Primary lymphoepithelial carcinoma
- Primary lymphoepithelial carcinoma of trachea
- Primary malignant epithelial neoplasm of trachea
- Primary malignant neoplasm of carina
- Primary malignant neoplasm of trachea
- Primary mucinous adenocarcinoma of trachea
- Primary mucinous cystadenocarcinoma of trachea
- Primary mucoepidermoid carcinoma of trachea
- Primary myoepithelial carcinoma of trachea
- Primary papillary adenocarcinoma of trachea
- Primary papillary squamous cell carcinoma of trachea
- Primary salivary gland type carcinoma of trachea
- Primary signet ring cell carcinoma of trachea
- Primary solid carcinoma of trachea
- Primary spindle cell carcinoma of trachea
- Primary spindle cell squamous cell carcinoma
- Primary squamous cell adenoid carcinoma of trachea
- Primary squamous cell carcinoma of trachea
- Primary undifferentiated carcinoma of trachea
- Primary verrucous carcinoma of trachea
- Primary verrucous squamous cell carcinoma
- Signet ring cell carcinoma of trachea
- Solid carcinoma of trachea
- Spindle cell carcinoma of trachea
- Squamous cell adenoid carcinoma of trachea
- Squamous cell carcinoma of trachea
- Undifferentiated carcinoma of trachea
- Verrucous carcinoma of trachea
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C33: its own notes plus those printed at block C30-C39 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.
- malignant neoplasm of middle ear
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- mesothelioma (C45.-)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
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 C33, its category, or a range that includes it.
Applicable To 2
These notes mention C33.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Malignant Tracheal Neoplasm
a primary or metastatic malignant neoplasm involving the trachea.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
Patient EducationClinical
Head and Neck Cancer
Head and neck cancer is the name for cancers that develop in the mouth, nose and sinuses, salivary glands, and throat and voice box (larynx). Most head and neck cancers are squamous cell cancers. They begin in the moist tissues that line the head and neck. The cancer cells may spread into deeper tissue as the cancer grows.
The full article covers:
- What is head and neck cancer?
- Who is more likely to develop head and neck cancer?
- What are the symptoms of head and neck cancer?
- How is head and neck cancer diagnosed?
- What are the treatments for head and neck cancer?
- Can head and neck cancer be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C33 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C33Overview
What is the ICD-10 code for malignant neoplasm of trachea?
The ICD-10-CM code for malignant neoplasm of trachea is C33. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C33 (Malignant neoplasm of trachea) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of trachea on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C33 group to?
When malignant neoplasm of trachea is the principal diagnosis on an inpatient stay, it groups to MS-DRG 181, 180, 182, with relative weights from 0.7436 to 1.7800 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C33 a CC or MCC?
CMS lists C33 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 46 closely related codes in its exclusion list.
Can C33 be reported with a code from C45?
Not as a rule. The Excludes1 note at block C30-C39, which applies to C33, lists "mesothelioma (C45.-)". 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 C33?
C33 (malignant neoplasm of trachea) 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 9 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 20.
Does C33 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C33 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.
