2027 ICD-10-CM Diagnosis Code C51.2Malignant neoplasm of clitoris

ICD-10-CM Codes›C00–D49›C51-C58›C51

ICD-10-CM C51.2
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

C51.2 is a billable ICD-10-CM diagnosis code for malignant neoplasm of clitoris. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 731 through 733, 754 through 756. Coders also document this condition as lesion of clitoris. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Female reproductive system cancers - all other types.

For Medicare Advantage risk adjustment, C51.2 maps to CMS-HCC Category 22 (Bladder, Colorectal, and Other Cancers) under the V28 model, adding a risk factor of about 0.363 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
C51.2
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of clitoris
Short Description
Malignant neoplasm of clitoris
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 CodeC51.2Malignant neoplasm of clitoris

Medicare Risk Adjustment (HCC)Billing

C51.2 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 22— Bladder, Colorectal, and Other Cancers
Payment HCC · PY 2027 one of 126 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.363
community, non-dual, aged · ranges 0.314–0.410 across segments
Hierarchy
Superseded by HCC 17, HCC 18, HCC 19, HCC 20, and HCC 21
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 11
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 11 · ESRD (V21): HCC 11 · ESRD (V24): HCC 11
ESRD V21 weights: 0.076 dialysis, 0.284–0.298 functioning graft · ESRD V24 weights: 0.059 dialysis, 0.257–0.362 functioning graft
Part D (RxHCC)
Not mapped
C51.2 does not risk-adjust in the RxHCC prescription drug model

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Lesion of clitoris
  • Malignant neoplasm of clitoris
  • Neoplasm of clitoris
  • Primary malignant neoplasm of clitoris

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to C51.2: its own notes plus those printed at C51, block C51-C58, and Chapter 2. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block C51-C58 Malignant neoplasms of female genital organs applies to 36 codes
  • malignant neoplasm of skin of female genital organs

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From C51 Malignant neoplasm of vulva applies to 5 codes
  • carcinoma in situ of vulva (D07.1)

Notes

General instructions on how these codes are used.

From Chapter 2 (C00-D49) Neoplasms applies to 1,730 codes
  • Functional activity
  • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
  • Morphology [Histology]
  • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
  • Primary malignant neoplasms overlapping site boundaries
  • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
  • Malignant neoplasm of ectopic tissue
  • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name C51.2, its category, or a range that includes it.

Applicable To 2

These notes mention C51.2.

  • Z80.4 Family history of malignant neoplasm of genital organs
    Conditions classifiable to C51-C63 names C51-C63, which includes this code
  • Z85.4 Personal history of malignant neoplasm of genital organs
    Conditions classifiable to C51-C63 names C51-C63, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming C51.2: they are not reported together with it, unless the two conditions are unrelated.

  • C44 Other and unspecified malignant neoplasm of skin
    malignant neoplasm of skin of genital organs (C51-C52, C60.-, C63.2) names C51-C52, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming C51.2: its condition is not part of those codes, and both may be reported when the patient has both.

  • C43 Malignant melanoma of skin
    malignant melanoma of skin of genital organs (C51-C52, C60.-, C63.-) names C51-C52, which includes this code

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

Clinical InformationClinical

  • Malignant Clitoral Neoplasm

    a malignant neoplasm that affects the clitoris.

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
clitorisC51.2C79.82D07.1D28.0D39.8D49.59
skin NOS › clitorisC51.2C79.82D07.1D28.0D39.8D49.59
skin NOS › female genital organs (external) › clitorisC51.2C79.82D07.1D28.0D39.8D49.59

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 C51.2 to ICD-9-CMHistory

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

ICD-9-CM
184.3 Malign neopl clitoris
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About C51.2Overview

What is the ICD-10 code for malignant neoplasm of clitoris?

The ICD-10-CM code for malignant neoplasm of clitoris is C51.2 (sometimes written as C512). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is C51.2 (Malignant neoplasm of vulva) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of clitoris on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does C51.2 group to?

When malignant neoplasm of clitoris is the principal diagnosis on an inpatient stay, it groups to MS-DRG 732, 755, 756, 754, 733, 731, with relative weights from 0.8583 to 3.5462 depending on complications. Higher weights mean higher Medicare reimbursement.

Can C51.2 be reported with D07.1?

Not as a rule. The Excludes1 note at C51, which applies to C51.2, lists "carcinoma in situ of vulva (D07.1)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of C51.2?

Under the General Equivalence Mappings, malignant neoplasm of clitoris converts to ICD-9-CM 184.3 (malign neopl clitoris). The mapping is a direct match.

What HCC is C51.2?

C51.2 (malignant neoplasm of clitoris) maps to CMS-HCC Category 22 (Bladder, Colorectal, and Other Cancers), commonly written as HCC 22, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 11 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.

Does C51.2 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, C51.2 adds a risk adjustment factor of about 0.363 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.314 to 0.410 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, and HCC 21) supersedes it when both are reported. See the full factor table on the HCC 22 category page.