2026 ICD-10-CM Diagnosis Code C51.8Malignant neoplasm of overlapping sites of vulva

ICD-10-CM Codes›C00–D49›C51-C58›C51

ICD-10-CM C51.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C51.8 is a billable ICD-10-CM diagnosis code for malignant neoplasm of overlapping sites of vulva. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 736 through 741, 754 through 756. Coders also document this condition as overlapping malignant neoplasm of vulva. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Female reproductive system cancers - all other types.

Code Identity

ICD-10-CM Code
C51.8
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of overlapping sites of vulva
Short Description
Malignant neoplasm of overlapping sites of vulva
Same as the full description in the CMS dataset.
Parent Code
C51
Malignant neoplasm of vulva

Code Classification

ChapterC00–D49Neoplasms
SectionC51-C58Malignant neoplasms of female genital organs
CategoryC51Malignant neoplasm of vulva
This CodeC51.8Malignant neoplasm of overlapping sites of vulva

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Overlapping malignant neoplasm of vulva

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Melanoma(malignant)
      • skin
        • vulva
          • overlapping sites

Clinical ClassificationClinical

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

CCSR NEO038
Female reproductive system cancers - all other types
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
skin NOS › vulva › overlapping lesionC51.8–––––

Patient EducationClinical

Vulvar Cancer

Vulvar cancer is a rare type of cancer. It forms in a woman's external genitals, called the vulva. The cancer usually grows slowly over several years. First, precancerous cells grow on vulvar skin. This is called vulvar intraepithelial neoplasia (VIN), or dysplasia. Not all VIN cases turn into cancer, but it is best to treat it early.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert C51.8 to ICD-9-CMHistory

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

ICD-9-CM
184.8 Mal neo female genit NEC
Approximate The match is approximate rather than exact.

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 C51.8Overview

Is C51.8 (Malignant neoplasm of vulva) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of overlapping sites of vulva on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C51.8 group to?

When malignant neoplasm of overlapping sites of vulva is the principal diagnosis on an inpatient stay, it groups to MS-DRG 736, 737, 738, 739, 740, 741, 754, 755, 756, with relative weights from 0.9605 to 3.5745 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C51.8?

Under the General Equivalence Mappings, malignant neoplasm of overlapping sites of vulva converts to ICD-9-CM 184.8 (mal neo female genit 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.