Oth malignant neoplasm of overlapping sites of skin

This code signifies a malignant skin neoplasm that originates in or extends across multiple adjacent or contiguous skin sites, making it impossible to assign to a single anatomical location. This includes primary skin cancers that have spread locally to an overlapping area or tumors whose exact point of origin within a region is unclear due to their extensive nature.

Apply this code when documentation clearly indicates a primary malignant neoplasm of the skin involving two or more overlapping anatomical sites, such as a tumor spanning the cheek and ear, or the trunk and upper extremity. The physician's notes must explicitly state the involvement of multiple, overlapping skin regions, precluding a more specific site assignment.

• Ensure the documentation specifies "overlapping sites" or similar language; otherwise, code to the most definitive single site.
• Do not use this code for metastatic skin cancer; it is for primary malignant neoplasms of the skin.
• Always sequence this code as the primary diagnosis when it represents the reason for the encounter.