2026 ICD-10-CM Diagnosis Code C48.0Malignant neoplasm of retroperitoneum

ICD-10-CM Codes›C00–D49›C45-C49›C48

ICD-10-CM C48.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C48.0 is a billable ICD-10-CM diagnosis code for malignant neoplasm of retroperitoneum. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 826 through 830, 843 through 845. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - all other types.

Code Identity

ICD-10-CM Code
C48.0
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of retroperitoneum
Short Description
Malignant neoplasm of retroperitoneum
Same as the full description in the CMS dataset.
Parent Code
C48
Malignant neoplasm of retroperitoneum and peritoneum

Code Classification

ChapterC00–D49Neoplasms
SectionC45-C49Malignant neoplasms of mesothelial and soft tissue
CategoryC48Malignant neoplasm of retroperitoneum and peritoneum
This CodeC48.0Malignant neoplasm of retroperitoneum

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Liposarcoma of retroperitoneum
  • Malignant neoplasm of perinephric tissue
  • Malignant neoplasm of retrocecal tissue
  • Malignant retroperitoneal neoplasm
  • Malignant teratoma
  • Malignant teratoma of retroperitoneum
  • Neoplasm of periadrenal tissue
  • Neoplasm of perirenal tissue
  • Neoplasm of retrocecal tissue
  • Primary giant cell sarcoma of retroperitoneum
  • Primary leiomyosarcoma of abdomen
  • Primary leiomyosarcoma of retroperitoneum
  • Primary liposarcoma of retroperitoneum
  • Primary malignant neoplasm of periadrenal tissue
  • Primary malignant neoplasm of perirenal tissue
  • Primary malignant neoplasm of retrocecal tissue
  • Primary malignant neoplasm of retroperitoneum
  • Primary sarcoma of retroperitoneum
  • Retroperitoneal sarcoma

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO021
Gastrointestinal cancers - all other types
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Retroperitoneal Sarcoma

    a sarcoma that occurs in the retroperitoneal region.

  • Retroperitoneal Sarcoma by AJCC v8 Stage|Soft Tissue Sarcoma Retroperitoneum by AJCC v8 Stage

    a term that refers to the staging of retroperitoneal soft tissue sarcoma, following the rules of the tnm ajcc v8 classification system. this staging system applies to common sarcomas in the retroperitoneum. (from ajcc 8th ed.)

  • Stage I Retroperitoneal Sarcoma AJCC v8|Stage I Retroperitoneal Sarcoma

    stage i includes: ia: (t1, n0, m0, g1, gx); ib: (t2, t3, t4, n0, m0, g1, gx). t1: tumor measuring 5 cm or less in greatest dimension. t2: tumor measuring more than 5 cm and less than or equal to 10 cm in greatest dimension. t3: tumor measuring more than 10 cm and less than or equal to 15 cm in greatest dimension. t4: tumor measuring more than 15 cm in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. m0: no distant metastasis. gx: grade cannot be assessed. g1: total differentiation, mitotic count and necrosis score of 2 or 3. (ajcc 8th ed.)

  • Stage IA Retroperitoneal Sarcoma AJCC v8|Stage IA Retroperitoneal Sarcoma|Stage IA Soft Tissue Retroperitoneal Sarcoma AJCC v8

    stage ia includes: t1, n0, m0, g1, gx. t1: tumor measuring 5 cm or less in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. m0: no distant metastasis. gx: grade cannot be assessed. g1: total differentiation, mitotic count and necrosis score of 2 or 3. (ajcc 8th ed.)

  • Stage IB Retroperitoneal Sarcoma AJCC v8|Stage IB Retroperitoneal Sarcoma|Stage IB Soft Tissue Retroperitoneal Sarcoma AJCC v8

    stage ib includes: t2, t3, t4, n0, m0, g1, gx. t2: tumor measuring more than 5 cm and less than or equal to 10 cm in greatest dimension. t3: tumor measuring more than 10 cm and less than or equal to 15 cm in greatest dimension. t4: tumor measuring more than 15 cm in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. m0: no distant metastasis. gx: grade cannot be assessed. g1: total differentiation, mitotic count and necrosis score of 2 or 3. (ajcc 8th ed.)

  • Stage II Retroperitoneal Sarcoma AJCC v8|Stage II Retroperitoneal Sarcoma|Stage II Soft Tissue Retroperitoneal Sarcoma AJCC v8

    stage ii includes: t1, n0, m0, g2, g3. t1: tumor measuring 5 cm or less in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. m0: no distant metastasis. g2: total differentiation, mitotic count and necrosis score of 4 or 5. g3: total differentiation, mitotic count and necrosis score of 6, 7, or 8. (ajcc 8th ed.)

  • Stage III Retroperitoneal Sarcoma AJCC v8|Stage III Retroperitoneal Sarcoma

    stage iii includes: iiia: (t2, n0, m0, g2, g3); iiib: (t3, t4, n0, m0, g2, g3); (any t, n1, m0, any g). t2: tumor measuring more than 5 cm and less than or equal to 10 cm in greatest dimension. t3: tumor measuring more than 10 cm and less than or equal to 15 cm in greatest dimension. t4: tumor measuring more than 15 cm in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. n1: regional lymph node metastasis. m0: no distant metastasis. g2: total differentiation, mitotic count and necrosis score of 4 or 5. g3: total differentiation, mitotic count and necrosis score of 6, 7, or 8. (ajcc 8th ed.)

  • Stage IIIA Retroperitoneal Sarcoma AJCC v8|Stage IIIA Retroperitoneal Sarcoma|Stage IIIA Soft Tissue Retroperitoneal Sarcoma AJCC v8

    stage iiia includes: t2, n0, m0, g2, g3. t2: tumor measuring more than 5 cm and less than or equal to 10 cm in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. m0: no distant metastasis. g2: total differentiation, mitotic count and necrosis score of 4 or 5. g3: total differentiation, mitotic count and necrosis score of 6, 7, or 8. (ajcc 8th ed.)

  • Stage IIIB Retroperitoneal Sarcoma AJCC v8|Stage IIIB Retroperitoneal Sarcoma|Stage IIIB Soft Tissue Retroperitoneal Sarcoma AJCC v8

    stage iiib includes: (t3, t4, n0, m0, g2, g3); (any t, n1, m0, any g). t3: tumor measuring more than 10 cm and less than or equal to 15 cm in greatest dimension. t4: tumor measuring more than 15 cm in greatest dimension. n0: no regional lymph node metastasis or unknown lymph node status. n1: regional lymph node metastasis. m0: no distant metastasis. g2: total differentiation, mitotic count and necrosis score of 4 or 5. g3: total differentiation, mitotic count and necrosis score of 6, 7, or 8. (ajcc 8th ed.)

  • Stage IV Retroperitoneal Sarcoma AJCC v8|Stage IV Retroperitoneal Sarcoma|Stage IV Soft Tissue Retroperitoneal Sarcoma AJCC v8

    stage iv includes: any t, any n, m1, any g. m1: distant metastasis. (ajcc 8th ed.)

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
connective tissue NEC › retroperitoneumC48.0C78.6–D20.0D48.3D49.0
paranephricC48.0C78.6–D20.0D48.3D49.0
periadrenal (tissue)C48.0C78.6–D20.0D48.3D49.0
perinephricC48.0C78.6–D20.0D48.3D49.0
peripancreaticC48.0C78.6–D20.0D48.3D49.0
perirenal (tissue)C48.0C78.6–D20.0D48.3D49.0
retrocecalC48.0C78.6–D20.0D48.3D49.0
retroperitoneal (space) (tissue)C48.0C78.6–D20.0D48.3D49.0
retroperitoneumC48.0C78.6–D20.0D48.3D49.0

Patient EducationClinical

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Convert C48.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
158.0 Mal neo retroperitoneum
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C48.0Overview

Is C48.0 (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 retroperitoneum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C48.0 group to?

When malignant neoplasm of retroperitoneum is the principal diagnosis on an inpatient stay, it groups to MS-DRG 826, 827, 828, 829, 830, 843, 844, 845, with relative weights from 0.8516 to 4.6778 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C48.0?

Under the General Equivalence Mappings, malignant neoplasm of retroperitoneum converts to ICD-9-CM 158.0 (mal neo retroperitoneum). The mapping is a direct match.

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.