C43.51 Malignant melanoma of anal skin

Billable ICD-10-CM code, FY2026.

Applicable to

• Malignant melanoma of anal margin
• Malignant melanoma of perianal skin

Applies from C43 Malignant melanoma of skin

Excludes1 (never code together)

• melanoma in situ (D03.-)

Excludes2 (not included here)

• malignant melanoma of skin of genital organs (C51-C52, C60.-, C63.-)
• Merkel cell carcinoma (C4A.-)
• sites other than skin-code to malignant neoplasm of the site

Applies from C43.5 Malignant melanoma of trunk

Excludes2 (not included here)

• malignant neoplasm of anus NOS (C21.0)
• malignant neoplasm of scrotum (C63.2)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 23 — Prostate, Breast, and Other Cancers and Tumors
• CMS-HCC V22: HCC 12 — Breast, Prostate, and Other Cancers and Tumors
• RxHCC V08: HCC 22 — Prostate, Breast, Bladder, and Other Cancers and Tumors
• ESRD V24: HCC 12

MS-DRG index

Defines the logic of DRG(s) 595-596 in MDC 09.

Approximate ICD-9-CM (GEMs)

• 172.5 Malignant melanoma of skin of trunk, except scrotum (approximate)

Code annotations containing back-references to C43.51

Back-references to C43.51

• Type 2 Excludes: C21 Malignant neoplasm of anus and anal canal ("malignant melanoma of anal margin (C43.51)")
• Type 2 Excludes: C21 Malignant neoplasm of anus and anal canal ("malignant melanoma of anal skin (C43.51)")
• Type 2 Excludes: C21 Malignant neoplasm of anus and anal canal ("malignant melanoma of perianal skin (C43.51)")

Back-references to C43

• Type 1 Excludes: C44 Other and unspecified malignant neoplasm of skin ("malignant melanoma of skin (C43.-)")

Diagnosis Index entries for C43.51

• Melanoma (malignant) › skin › anus, anal (skin)
• Melanoma (malignant) › skin › perianal skin
• Melanoma (malignant) › skin › perineum

Nearby codes

• C43.30 Malignant melanoma of unspecified part of face
• C43.31 Malignant melanoma of nose
• C43.39 Malignant melanoma of other parts of face
• C43.4 Malignant melanoma of scalp and neck
• C43.5 Malignant melanoma of trunk
• C43.51 Malignant melanoma of anal skin (this code)
• C43.52 Malignant melanoma of skin of breast
• C43.59 Malignant melanoma of other part of trunk
• C43.6 Malignant melanoma of upper limb, including shoulder
• C43.60 Malignant melanoma of unspecified upper limb, including shoulder
• C43.61 Malignant melanoma of right upper limb, including shoulder