Osteitis deformans in neoplastic diseases, unspecified site

This code describes Paget's disease of bone (osteitis deformans) that occurs as a secondary condition in patients with a primary neoplastic disease. It indicates a bone remodeling disorder characterized by excessive bone breakdown and disorganized new bone formation, specifically when linked to a cancer diagnosis, with the affected bone site not specified.

Use this code when documentation clearly links osteitis deformans to a co-existing neoplastic disease, and the specific anatomical location of the Paget's disease is not documented. This code is appropriate when the physician explicitly states "osteitis deformans secondary to neoplasm" or similar phrasing, without specifying the affected bone.

• Always sequence the underlying neoplastic disease code first, as M90.60 is a manifestation code.
• Avoid using this code if a specific site of osteitis deformans is documented; instead, use the more specific M90.6- subcategories.
• Ensure documentation clearly establishes the causal link between the neoplasm and the osteitis deformans, not just co-occurrence.