Neoplasm of uncertain behavior, unspecified

This code signifies a tumor or abnormal growth where the pathologist cannot definitively classify it as benign or malignant based on microscopic examination. The behavior of the neoplasm – whether it will remain localized or has the potential to invade surrounding tissues or metastasize – is currently unknown.

Assign this code when pathology reports describe a neoplasm as "uncertain behavior," "borderline," or "indeterminate" and no further specificity regarding its nature is provided. This is typically an interim diagnosis while further studies or clinical observation are pending. Documentation must clearly state the uncertainty of the neoplasm's biological potential.

• Avoid using this code if the pathology report provides a more specific diagnosis (e.g., benign, malignant, or in situ).
• Always review the final pathology report; this code is often temporary and may be replaced by a more definitive code.
• Do not use this code for neoplasms that are explicitly stated as benign or malignant, even if the specific type is unknown.