ICD-10 Code C44.591 – Other specified malignant neoplasm of skin of breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C44.591 – Other specified malignant neoplasm of skin of breast
What it is
C44.591 identifies a malignant skin neoplasm located on the breast when the documentation does not fit a more specific skin cancer code. Use it for a confirmed skin malignancy of the breast, not for breast parenchymal cancer.
Clinical signs
Clinical features vary; refer to documentation. You may see a suspicious skin lesion on the breast with biopsy-confirmed malignancy, such as a nonmelanoma skin cancer or other specified malignant skin tumor.
When to use this code
Use this code when the provider documents a malignant neoplasm arising in the skin of the breast and no more specific ICD-10-CM skin cancer code applies. It is appropriate when the record clearly distinguishes the lesion from primary breast cancer. Check documentation if the site or histology is unclear.
Do not use for
Do not use this code for malignant neoplasm of the breast tissue itself, metastatic disease to the breast skin, or unspecified skin cancer when a more specific code is documented. Check documentation.
Coding tip
Verify the exact anatomic site and whether the malignancy is cutaneous before assigning C44.591.