2027 ICD-10-CM Diagnosis Code C45Mesothelioma

ICD-10-CM Codes›C00–D49›C45-C49›C45

ICD-10-CM C45
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

C45 is a non-billable ICD-10-CM category code for mesothelioma, so it cannot be submitted on claims. Use a more specific code from this category instead, such as C45.0, C45.1, C45.2, and C45.7.

Code Identity

ICD-10-CM Code
C45
Billable Status
No — Non-Billable Category
Code Describes
Mesothelioma
Short Description
Mesothelioma
Same as the full description in the CMS dataset.
Chapter
C45-C49
Malignant neoplasms of mesothelial and soft tissue

Code Classification

ChapterC00–D49Neoplasms
SectionC45-C49Malignant neoplasms of mesothelial and soft tissue
CategoryC45Mesothelioma
This CodeC45Mesothelioma

Specific Coding for MesotheliomaOverview

Non-specific codes like C45 require more characters. Use one of these billable codes instead:

  • Use C45.0 for Mesothelioma of pleura

  • Use C45.1 for Mesothelioma of peritoneum

  • Use C45.2 for Mesothelioma of pericardium

  • Use C45.7 for Mesothelioma of other sites

  • Use C45.9 for Mesothelioma, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to C45: its own notes plus those printed at Chapter 2. A note printed at a category, block or chapter applies to every code under it.

Notes

General instructions on how these codes are used.

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 C45, its category, or a range that includes it.

Applicable To 1

These notes mention C45.

  • Z85.83 Personal history of malignant neoplasm of bone and soft tissue
    Conditions classifiable to C40-C41; C45-C49

Excludes1 3

These codes carry an Excludes1 note naming C45: they are not reported together with it, unless the two conditions are unrelated.

  • Block C30-C39 Malignant neoplasms of respiratory and intrathoracic organs
    mesothelioma (C45.-)
  • C38 Malignant neoplasm of heart, mediastinum and pleura
    mesothelioma (C45.-)
  • C48 Malignant neoplasm of retroperitoneum and peritoneum
    mesothelioma (C45.-)

Excludes2 1

These codes carry an Excludes2 note naming C45: its condition is not part of those codes, and both may be reported when the patient has both.

  • C49 Malignant neoplasm of other connective and soft tissue
    mesothelioma (C45.-)

Clinical InformationClinical

  • Mesothelioma

    a tumor derived from mesothelial tissue (peritoneum, pleura, pericardium). it appears as broad sheets of cells, with some regions containing spindle-shaped, sarcoma-like cells and other regions showing adenomatous patterns. pleural mesotheliomas have been linked to exposure to asbestos. (dorland, 27th ed)

Patient EducationClinical

Mesothelioma

The tissue that lines your lungs, stomach, heart, and other organs is called mesothelium. Mesothelioma, also known as malignant mesothelioma, is cancer of that tissue. It usually starts in the lungs, but can also start in the abdomen or other organs.

Read the full article at MedlinePlus

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

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 C45Overview

What is the ICD-10 code for mesothelioma?

C45 is the ICD-10-CM category for mesothelioma, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is C45 (Mesothelioma) a billable code?

No. This is a category header that groups the codes for mesothelioma, and headers cannot be submitted on claims. Claims for mesothelioma need a more specific code from this category, such as C45.0, C45.1, and C45.2.