Unspecified malignant neoplasm of overlapping sites of skin

This code signifies a cancerous growth originating from the skin that involves multiple, contiguous anatomical sites, where the primary site cannot be definitively determined. It indicates that the malignancy spans across different areas of the skin, making it impossible to pinpoint a single point of origin.

Use this code when documentation clearly states a malignant skin neoplasm affecting overlapping sites, and the specific primary site is not identified. This is appropriate when the physician describes the lesion as "overlapping" or "spanning multiple sites" without further anatomical specificity.

• Avoid using this code if the documentation specifies a primary site, even if it extends to adjacent areas; instead, code the primary site.
• Ensure the physician's documentation explicitly states "overlapping sites" or similar language to support this code.
• Do not use this code if the malignancy is described as metastatic to the skin; instead, code the primary malignancy and the secondary site.