ICD-10-CM 2027 diagnosis code
C48.1Malignant neoplasm of specified parts of peritoneum
C48.1 is a valid, billable ICD-10-CM code for malignant neoplasm of specified parts of peritoneum. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About C48.1
C48.1 is the ICD-10-CM diagnosis code for malignant neoplasm of specified parts of peritoneum. It belongs to category C48 (malignant neoplasm of retroperitoneum and peritoneum), block C45-C49 (malignant neoplasms of mesothelial and soft tissue) and chapter 2 (neoplasms). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within C48 (malignant neoplasm of retroperitoneum and peritoneum), C48.1 is specifically for malignant neoplasm of specified parts of peritoneum. Related codes cover retroperitoneum (C48.0), peritoneum, unspecified (C48.2) and overlapping sites of retroperitoneum and peritoneum (C48.8).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 374 (Digestive Malignancy with MCC, relative weight 2.1109), DRG 375 (Digestive Malignancy with CC, relative weight 1.1838) and DRG 376 (Digestive Malignancy without CC/MCC, relative weight 0.8929), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 158.8 (malignant neoplasm of specified parts of peritoneum).
Coding notes
- 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
Notes that apply from higher levels
Instructions written at a parent level also apply to C48.1.
Broader instructions also apply from Chapter 2: Neoplasms.
Table of Drugs & Neoplasms entries
- Neoplasm, neoplastic › cul-de-sac (Douglas') — Malignant Primary
- Neoplasm, neoplastic › Douglas' cul-de-sac or pouch — Malignant Primary
- Neoplasm, neoplastic › mesentery, mesenteric — Malignant Primary
- Neoplasm, neoplastic › mesoappendix — Malignant Primary
- Neoplasm, neoplastic › mesocolon — Malignant Primary
- Neoplasm, neoplastic › omentum — Malignant Primary
- Neoplasm, neoplastic › peritoneum, peritoneal (cavity) › parietal — Malignant Primary
- Neoplasm, neoplastic › peritoneum, peritoneal (cavity) › pelvic — Malignant Primary
- Neoplasm, neoplastic › peritoneum, peritoneal (cavity) › specified part NEC — Malignant Primary
- Neoplasm, neoplastic › rectouterine pouch — Malignant Primary
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 06 · Diseases and Disorders of the Digestive System
ICD-9-CM equivalent
Converter →- 158.8Malignant neoplasm of specified parts of peritoneumapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about C48.1
Is C48.1 billable?
- Yes. C48.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can C48.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict C48.1 as a principal diagnosis.
Is C48.1 a CC or MCC?
- C48.1 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does C48.1 group to?
- C48.1 is used in the MS-DRG v44.0 logic for MS-DRG 374 (Digestive Malignancy with MCC), MS-DRG 375 (Digestive Malignancy with CC) and MS-DRG 376 (Digestive Malignancy without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for C48.1?
- The CMS General Equivalence Mappings map C48.1 to ICD-9-CM 158.8.