2026 ICD-10-CM Diagnosis Code C51.9Malignant neoplasm of vulva, unspecified
ICD-10-CM Codes›C00–D49›C51-C58›C51
- Billable — Valid for Submission
- Chronic Condition
C51.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of vulva, unspecified. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Female reproductive system cancers - vulva.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adenocarcinoma of anogenital mammary-like glands
- Adnexal carcinoma of vulva
- Anogenital verrucous carcinoma of Buschke-Löwenstein
- Basal cell carcinoma of vulva
- Carcinoma of vulva
- FIGO stage finding for vulvar melanoma
- FIGO VM stage V
- Infective dermatosis of female genitalia
- Invasive vulval Paget's disease
- Malignant melanoma of perineum
- Malignant melanoma of skin of perineum
- Malignant melanoma of skin of vulva
- Malignant melanoma of vulva
- Malignant neoplasm of vulva
- Paget's disease of vulva
- Primary adenocarcinoma of vulva
- Primary adnexal carcinoma of vulva
- Primary extramammary Paget disease of skin
- Primary invasive vulval Paget disease
- Primary malignant neoplasm of vulva
- Primary Paget disease of vulva
- Recurrent primary malignant neoplasm of vulva
- Sarcoma of vulva
- Squamous cell carcinoma of anogenital area
- Squamous cell carcinoma of vulva
- Squamous cell carcinoma of vulva due to lichen sclerosus
- Vulval verrucous carcinoma of Buschke-Löwenstein
- Vulvovaginal rhabdomyosarcoma
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of external female genitalia NOS
- Malignant neoplasm of pudendum
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
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
- female genital organ (external) NEC
- Melanoma(malignant)
- skin
- labium
- Melanoma(malignant)
- skin
- pudendum
- Melanoma(malignant)
- skin
- vulva
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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. |
|---|---|---|---|---|---|---|
| fourchette | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| labia (skin) | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| labium (skin) | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| mons | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| mons › pubis | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| mons › veneris | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| pudenda, pudendum (femaie) | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| skin NOS › female genital organs (external) | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| skin NOS › female genital organs (external) › labium NEC | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| skin NOS › female genital organs (external) › pudendum | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| skin NOS › female genital organs (external) › vulva | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| skin NOS › vulva | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
| vulva | C51.9 | C79.82 | D07.1 | D28.0 | D39.8 | D49.59 |
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 C51.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C51.9Overview
Is C51.9 (Malignant neoplasm of vulva) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of vulva, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C51.9 group to?
When malignant neoplasm of vulva, unspecified 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 C51.9?
Under the General Equivalence Mappings, malignant neoplasm of vulva, unspecified converts to ICD-9-CM 184.4 (malign neopl vulva NOS). 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.
