C44.500 Unspecified malignant neoplasm of anal skin

Billable ICD-10-CM code, FY2026.

Applicable to

• Unspecified malignant neoplasm of anal margin
• Unspecified malignant neoplasm of perianal skin

Applies from C44 Other and unspecified malignant neoplasm of skin

Includes

• malignant neoplasm of sebaceous glands
• malignant neoplasm of sweat glands

Excludes1 (never code together)

• Kaposi's sarcoma of skin (C46.0)
• malignant melanoma of skin (C43.-)
• malignant neoplasm of skin of genital organs (C51-C52, C60.-, C63.2)
• Merkel cell carcinoma (C4A.-)

Applies from C44.5 Other and unspecified malignant neoplasm of skin of trunk

Excludes1 (never code together)

• anus NOS (C21.0)
• scrotum (C63.2)

MS-DRG index

Defines the logic of DRG(s) 606-607 in MDC 09.

Approximate ICD-9-CM (GEMs)

• 173.50 Unspecified malignant neoplasm of skin of trunk, except scrotum (approximate)

Code annotations containing back-references to C44.500

Back-references to C44.500

• Type 2 Excludes: C21 Malignant neoplasm of anus and anal canal ("other and unspecified malignant neoplasm of anal margin (C44.500, C44.510, C44.520, C44.590)")
• Type 2 Excludes: C21 Malignant neoplasm of anus and anal canal ("other and unspecified malignant neoplasm of anal skin (C44.500, C44.510, C44.520, C44.590)")
• Type 2 Excludes: C21 Malignant neoplasm of anus and anal canal ("other and unspecified malignant neoplasm of perianal skin (C44.500, C44.510, C44.520, C44.590)")

Back-references to C44

• Type 1 Excludes: C76 Malignant neoplasm of other and ill-defined sites ("malignant neoplasm of skin (C44.-)")

Nearby codes

• C44.41 Basal cell carcinoma of skin of scalp and neck
• C44.42 Squamous cell carcinoma of skin of scalp and neck
• C44.49 Other specified malignant neoplasm of skin of scalp and neck
• C44.5 Other and unspecified malignant neoplasm of skin of trunk
• C44.50 Unspecified malignant neoplasm of skin of trunk
• C44.500 Unspecified malignant neoplasm of anal skin (this code)
• C44.501 Unspecified malignant neoplasm of skin of breast
• C44.509 Unspecified malignant neoplasm of skin of other part of trunk
• C44.51 Basal cell carcinoma of skin of trunk
• C44.510 Basal cell carcinoma of anal skin
• C44.511 Basal cell carcinoma of skin of breast