2026 ICD-10-CM Diagnosis Code D48.3Neoplasm of uncertain behavior of retroperitoneum
ICD-10-CM Codes›C00–D49›D37-D48›D48
- Billable — Valid for Submission
- Not Chronic
D48.3 is a billable ICD-10-CM diagnosis code for neoplasm of uncertain behavior of retroperitoneum. 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.
- Hemangioendothelioma
- Hemangioendothelioma of abdomen
- Hemangioendothelioma of retroperitoneum
- Neoplasm of periadrenal tissue
- Neoplasm of perirenal tissue
- Neoplasm of peritoneum and retroperitoneum
- Neoplasm of retrocecal tissue
- Neoplasm of uncertain behavior of periadrenal tissue
- Neoplasm of uncertain behavior of perirenal tissue
- Neoplasm of uncertain behavior of retrocecal tissue
- Neoplasm of uncertain behavior of retroperitoneum
- Neoplasm of uncertain behavior of retroperitoneum and peritoneum
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Fibromatosis - M72.9
- retroperitoneal - D48.3
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Fibromatosis
- retroperitoneal
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Hemangioendothelioma
a neoplasm derived from blood vessels, characterized by numerous prominent endothelial cells that occur singly, in aggregates, and as the lining of congeries of vascular tubes or channels. hemangioendotheliomas are relatively rare and are of intermediate malignancy (between benign hemangiomas and conventional angiosarcomas). they affect men and women about equally and rarely develop in childhood. (from stedman, 25th ed; holland et al., cancer medicine, 3d ed, p1866)Hemangioendothelioma, Epithelioid
a tumor of medium-to-large veins, composed of plump-to-spindled endothelial cells that bulge into vascular spaces in a tombstone-like fashion. these tumors are thought to have borderline aggression, where one-third develop local recurrences, but only rarely metastasize. it is unclear whether the epithelioid hemangioendothelioma is truly neoplastic or an exuberant tissue reaction, nor is it clear if this is equivalent to kimura's disease (see angiolymphoid hyperplasia with eosinophilia). (segen, dictionary of modern medicine, 1992)Angiolymphoid Hyperplasia with Eosinophilia
solitary or multiple benign cutaneous nodules comprised of immature and mature vascular structures intermingled with endothelial cells and a varied infiltrate of eosinophils, histiocytes, lymphocytes, and mast cells.
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. |
|---|---|---|---|---|---|---|
| connective tissue NEC › retroperitoneum | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| paranephric | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| periadrenal (tissue) | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| perinephric | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| peripancreatic | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| perirenal (tissue) | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| retrocecal | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| retroperitoneal (space) (tissue) | C48.0 | C78.6 | – | D20.0 | D48.3 | D49.0 |
| retroperitoneum | C48.0 | C78.6 | – | D20.0 | D48.3 | 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
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Convert D48.3 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D48.3Overview
Is D48.3 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report neoplasm of uncertain behavior of retroperitoneum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D48.3 group to?
When neoplasm of uncertain behavior of retroperitoneum 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 D48.3?
Under the General Equivalence Mappings, neoplasm of uncertain behavior of retroperitoneum 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.
