C51.9 — Malignant neoplasm of vulva, unspecified
Is C51.9 billable?
Yes, but C51.9 is an unspecified code. C51.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, C51.9 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting C51.9 — the more specific alternatives are listed below.
C51.9 at a glance
| Code | C51.9 |
|---|---|
| Description | Malignant neoplasm of vulva, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does C51.9 group to?
C51.9 sits in MDC 13 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 731Uterine and Adnexa Procedures for Malignancy with MCCsurgical
- 732Uterine and Adnexa Procedures for Malignancy with CCsurgical
- 733Uterine and Adnexa Procedures for Malignancy without CC/MCCsurgical
How is C51.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to C51.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Melanoma › skin › female genital organNEC (malignant)
- Melanoma › skin › labium (malignant)
- Melanoma › skin › pudendum (malignant)
- Melanoma › skin › vulva (malignant)
Inclusion terms
Alternative wording in documentation that is classified to C51.9.
- Malignant neoplasm of external female genitalia NOS
- Malignant neoplasm of pudendum
Excludes1 — never code together — inherited from C51
The conditions below can never be reported together with C51.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- carcinoma in situ of vulva (D07.1)
How long has C51.9 existed?
C51.9 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.