C51.9 Malignant neoplasm of vulva, unspecified

Billable ICD-10-CM code, FY2026.

Applicable to

• Malignant neoplasm of external female genitalia NOS
• Malignant neoplasm of pudendum

Applies from C51 Malignant neoplasm of vulva

Excludes1 (never code together)

• carcinoma in situ of vulva (D07.1)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 22 — Bladder, Colorectal, and Other Cancers
• CMS-HCC V22: HCC 11 — Colorectal, Bladder, and Other Cancers
• ESRD V24: HCC 11

MS-DRG index

Defines the logic of DRG(s) 736-741 in MDC 13.

Approximate ICD-9-CM (GEMs)

• 184.4 Malignant neoplasm of vulva, unspecified site

Code annotations containing back-references to C51.9

Back-references to C51

• Type 2 Excludes: C43 Malignant melanoma of skin ("malignant melanoma of skin of genital organs (C51-C52, C60.-, C63.-)")
• Type 1 Excludes: C44 Other and unspecified malignant neoplasm of skin ("malignant neoplasm of skin of genital organs (C51-C52, C60.-, C63.2)")

Diagnosis Index entries for C51.9

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

Nearby codes

• C51 Malignant neoplasm of vulva
• C51.0 Malignant neoplasm of labium majus
• C51.1 Malignant neoplasm of labium minus
• C51.2 Malignant neoplasm of clitoris
• C51.8 Malignant neoplasm of overlapping sites of vulva
• C51.9 Malignant neoplasm of vulva, unspecified (this code)