Neoplasm of uncertain behavior of skin

This code signifies a skin lesion or growth that has been identified as a neoplasm, but its biological behavior (whether it is benign or malignant) cannot be definitively determined from the pathology. It represents an intermediate category where further observation or investigation may be required.

Apply this code when pathology reports describe a skin neoplasm as "uncertain behavior," "borderline," or "of undetermined malignant potential." This is typically used when a definitive diagnosis of benign or malignant cannot be established after initial histological examination.

• Do not use this code if the pathology definitively states benign or malignant; instead, code to the appropriate benign or malignant neoplasm of the skin.
• Always review the complete pathology report for the most specific diagnosis; avoid coding from operative notes alone if a pathology report is available.
• If subsequent pathology or clinical follow-up clarifies the behavior, update the diagnosis to the more specific benign or malignant code.