2026 ICD-10-CM Diagnosis Code C48.1Malignant neoplasm of specified parts of peritoneum
ICD-10-CM Codes›C00–D49›C45-C49›C48
- Billable — Valid for Submission
- Chronic Condition
C48.1 is a billable ICD-10-CM diagnosis code for malignant neoplasm of specified parts of peritoneum. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 374 through 376. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - peritoneum.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Malignant neoplasm of mesentery
- Malignant neoplasm of mesocecum
- Malignant neoplasm of mesocolon
- Malignant neoplasm of mesorectum
- Malignant neoplasm of omentum
- Malignant neoplasm of pelvic peritoneum
- Malignant neoplasm of the pouch of Douglas
- Neoplasm of omentum
- Neoplasm of rectouterine pouch
- Neoplasm of the mesocolon
- Primary malignant neoplasm of omentum
- Primary malignant neoplasm of parietal peritoneum
- Primary malignant neoplasm of pelvic peritoneum
- Primary malignant neoplasm of rectouterine pouch
- Primary malignant neoplasm of the mesentery
- Primary malignant neoplasm of the mesocolon
- Primary myosarcoma of omentum
- Primary sarcoma of peritoneum
- Primary sarcoma of soft tissues of abdomen
- Sarcoma of mesentery
- Sarcoma of omentum
- Sarcoma of pelvic peritoneum
- Sarcoma of peritoneum
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of cul-de-sac
- Malignant neoplasm of mesentery
- Malignant neoplasm of mesocolon
- Malignant neoplasm of omentum
- Malignant neoplasm of parietal peritoneum
- Malignant neoplasm of pelvic peritoneum
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Mesocolon
the fold of peritoneum by which the colon is attached to the posterior abdominal wall.Omentum
a double-layered fold of peritoneum that attaches the stomach to other organs in the abdominal cavity.
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. |
|---|---|---|---|---|---|---|
| cul-de-sac (Douglas') | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| Douglas' cul-de-sac or pouch | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| mesentery, mesenteric | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| mesoappendix | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| mesocolon | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| omentum | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| peritoneum, peritoneal (cavity) › parietal | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| peritoneum, peritoneal (cavity) › pelvic | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| peritoneum, peritoneal (cavity) › specified part NEC | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| rectouterine pouch | C48.1 | C78.6 | – | D20.1 | D48.4 | D49.0 |
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Convert C48.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C48.1Overview
Is C48.1 (Malignant neoplasm of retroperitoneum and peritoneum) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of specified parts of peritoneum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C48.1 group to?
When malignant neoplasm of specified parts of peritoneum is the principal diagnosis on an inpatient stay, it groups to MS-DRG 374, 375, 376, with relative weights from 0.9243 to 2.1387 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C48.1?
Under the General Equivalence Mappings, malignant neoplasm of specified parts of peritoneum converts to ICD-9-CM 158.8 (mal neo peritoneum NEC). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
