Is C51.9 a billable ICD-10-CM code?

Yes. C51.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does C51.9 sit in the tabular list?

Neoplasms (C00-D49), in the block Malignant neoplasms of female genital organs (C51-C58).

What cannot be coded together with C51.9?

C51.9 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above C51.9 (C51) and apply to it just the same.

C51.9

C51.9 — Malignant neoplasm of vulva, unspecified

Billable / specific codeICD-10-CM

C51.9 is a billable, specific ICD-10-CM code for malignant neoplasm of vulva, unspecified. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

Malignant neoplasm of external female genitalia NOS
Malignant neoplasm of pudendum

Excludes1 inherited from the categories above C51.9

These are not written on C51.9, but they bind it: a note on a category applies to every code beneath it. Billing C51.9 with anything listed here is a denial.

Written on C51 — Malignant neoplasm of vulva

carcinoma in situ of vulva (D07.1)

Risk adjustment

C51.9 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

HCC 22 Bladder, Colorectal, and Other Cancers0.363 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

C51.9 is named in 54 Medicare coverage policies — 54 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A52450Billing and Coding: Paclitaxel (e.g., Taxol®/Abraxane ™)
A52479Oral Anticancer Drugs - Policy Article
A52480Oral Antiemetic Drugs (Replacement for Intravenous Antiemetics) - Policy Article
A55717Billing and Coding: Lab: Flow Cytometry

How C51.9 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to C51.9.

Melanoma›skin›female genital organ NEC(external)
Melanoma›skin›labium
Melanoma›skin›pudendum
Melanoma›skin›vulva

Code history

C51.9 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share C51. If C51.9 is not quite right, the correct code is usually one of these.

Questions about C51.9

Is C51.9 a billable ICD-10-CM code?: Yes. C51.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does C51.9 sit in the tabular list?: Neoplasms (C00-D49), in the block Malignant neoplasms of female genital organs (C51-C58).
What cannot be coded together with C51.9?: C51.9 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above C51.9 (C51) and apply to it just the same.