ICD-10 Code for Mesothelioma
Also indexed as (malignant)
The ICD-10-CM code for mesothelioma is C45.9 — Mesothelioma, unspecified. This is the code the Alphabetic Index gives for mesothelioma with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).
C45.9 is billable but unspecified. If the documentation names a type, site or cause, one of the more specific codes below is likely expected.
Which mesothelioma code should you use?
The Alphabetic Index lists 10 codes under Mesothelioma. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.
By type
Mesothelioma benign
| mesentery | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| mesocolon | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| omentum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| peritoneum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| pleura | D19.0 | Benign neoplasm of mesothelial tissue of pleura | |
| specified site NEC | D19.7 | Benign neoplasm of mesothelial tissue of other sites | |
| unspecified site | D19.9 | Benign neoplasm of mesothelial tissue, unspecified |
Mesothelioma site classification
| liver | C45.7 | Mesothelioma of other sites | |
| lung | C45.7 | Mesothelioma of other sites | |
| mediastinum | C45.7 | Mesothelioma of other sites | |
| mesentery | C45.1 | Mesothelioma of peritoneum | |
| mesocolon | C45.1 | Mesothelioma of peritoneum | |
| omentum | C45.1 | Mesothelioma of peritoneum | |
| pericardium | C45.2 | Mesothelioma of pericardium | |
| peritoneum | C45.1 | Mesothelioma of peritoneum | |
| pleura | C45.0 | Mesothelioma of pleura | |
| retroperitoneum | C45.7 | Mesothelioma of other sites | |
| specified site NEC | C45.7 | Mesothelioma of other sites | |
| unspecified | C45.9 | Mesothelioma, unspecified | |
| pleura › parietal | C45.0 | Mesothelioma of pleura |
Mesothelioma biphasic
| benign › mesentery | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › mesocolon | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › omentum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › peritoneum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › pleura | D19.0 | Benign neoplasm of mesothelial tissue of pleura | |
| benign › specified site NEC | D19.7 | Benign neoplasm of mesothelial tissue of other sites | |
| benign › unspecified site | D19.9 | Benign neoplasm of mesothelial tissue, unspecified |
Mesothelioma epithelioid
| benign › mesentery | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › mesocolon | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › omentum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › peritoneum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › pleura | D19.0 | Benign neoplasm of mesothelial tissue of pleura | |
| benign › specified site NEC | D19.7 | Benign neoplasm of mesothelial tissue of other sites | |
| benign › unspecified site | D19.9 | Benign neoplasm of mesothelial tissue, unspecified |
Mesothelioma fibrous
| benign › mesentery | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › mesocolon | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › omentum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › peritoneum | D19.1 | Benign neoplasm of mesothelial tissue of peritoneum | |
| benign › pleura | D19.0 | Benign neoplasm of mesothelial tissue of pleura | |
| benign › specified site NEC | D19.7 | Benign neoplasm of mesothelial tissue of other sites | |
| benign › unspecified site | D19.9 | Benign neoplasm of mesothelial tissue, unspecified |
Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources