2026 ICD-10-CM Diagnosis Code D48.4Neoplasm of uncertain behavior of peritoneum
ICD-10-CM Codes›C00–D49›D37-D48›D48
- Billable — Valid for Submission
- Not Chronic
D48.4 is a billable ICD-10-CM diagnosis code for neoplasm of uncertain behavior 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 Neoplasms of unspecified nature or uncertain behavior.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Leiomyomatosis peritonealis disseminata
- Mesothelioma of mesocolon
- Neoplasm of omentum
- Neoplasm of peritoneum and retroperitoneum
- Neoplasm of rectouterine pouch
- Neoplasm of the mesocolon
- Neoplasm of uncertain behavior of omentum
- Neoplasm of uncertain behavior of parietal peritoneum
- Neoplasm of uncertain behavior of pelvic peritoneum
- Neoplasm of uncertain behavior of peritoneum
- Neoplasm of uncertain behavior of rectouterine pouch
- Neoplasm of uncertain behavior of retroperitoneum
- Neoplasm of uncertain behavior of retroperitoneum and peritoneum
- Neoplasm of uncertain behavior of the mesentery
- Neoplasm of uncertain behavior of the mesocolon
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Mesothelioma (malignant) - C45.9
- cystic - D48.4
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Mesothelioma(malignant)
- cystic
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. |
|---|---|---|---|---|---|---|
| cavity › peritoneal | C48.2 | C78.6 | – | D20.1 | D48.4 | D49.0 |
| 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) | C48.2 | 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 |
Patient EducationClinical
Peritoneal Disorders
Your peritoneum is the tissue that lines your abdominal wall and covers most of the organs in your abdomen. A liquid, peritoneal fluid, lubricates the surface of this tissue.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert D48.4 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D48.4Overview
Is D48.4 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report neoplasm of uncertain behavior of peritoneum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D48.4 group to?
When neoplasm of uncertain behavior 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 D48.4?
Under the General Equivalence Mappings, neoplasm of uncertain behavior of peritoneum converts to ICD-9-CM 235.4 (unc behav neo peritoneum). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
