ICD-10 Code C44.590 – Other specified malignant neoplasm of anal skin (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C44.590 – Other specified malignant neoplasm of anal skin
What it is
This code identifies a malignant skin tumor located on the anal skin when the documentation specifies another type not named elsewhere in ICD-10-CM. Use it for a cancerous lesion arising from the skin around the anus, not the anal canal.
Clinical signs
Clinical features vary; refer to documentation. You may see a persistent, abnormal skin lesion near the anus that is suspicious for malignancy and confirmed by pathology or specialist assessment.
When to use this code
Use this code when the provider documents a malignant neoplasm of anal skin and the exact histology or subtype is not captured by a more specific code. It is appropriate when the lesion is on the external anal skin, not the mucosal anal canal. Check documentation if the site is described ambiguously.
Do not use for
Do not use for malignant neoplasms of the anal canal, rectum, or other perianal sites unless the record clearly states anal skin. Do not assign it for benign, premalignant, or unspecified skin lesions.
Coding tip
Verify the anatomic site carefully; “anal” does not always mean anal skin, so code only what the documentation explicitly supports.