Neoplasm of uncertain behavior of bone and articular cartilage

This code signifies a tumor originating in the bone or articular cartilage whose biological behavior (benign vs. malignant) cannot be definitively determined from pathological examination. These neoplasms exhibit features that are neither clearly benign nor overtly malignant, requiring further investigation or monitoring.

Use this code when pathology reports describe a bone or cartilage lesion as "uncertain behavior," "borderline," or "of unknown malignant potential." Documentation must explicitly state the neoplasm's uncertain nature and its origin in bone or articular cartilage.

• Do not use this code if the pathology definitively states benign or malignant; instead, use the appropriate benign or malignant neoplasm code.
• Carefully review the pathology report for specific terminology indicating uncertain behavior.
• This code is often a temporary assignment pending further diagnostic workup or re-excision.