Osteitis deformans in neoplastic diseases, unspecified thigh

This code signifies Paget's disease of bone occurring in the context of a neoplastic process, specifically affecting an unspecified thigh. It describes a chronic bone disorder characterized by abnormal bone remodeling, leading to enlarged and weakened bones, when it co-occurs with cancer. The "unspecified thigh" indicates that the laterality (right or left) of the affected thigh is not documented.

Use this code when documentation clearly indicates a diagnosis of Paget's disease of bone (osteitis deformans) in a patient who also has a neoplastic disease, and the Paget's disease is located in the thigh, but the specific side is not specified. Supporting documentation would include physician notes detailing both diagnoses and the anatomical site of the Paget's disease.

• Always sequence the neoplastic disease code first, followed by this code, as the Paget's disease is secondary to the neoplasm.
• Avoid using this code if the laterality of the affected thigh (right or left) is specified; instead, use the more specific codes M90.651 or M90.652.
• Ensure documentation explicitly links the osteitis deformans to the neoplastic disease; otherwise, a standalone Paget's disease code (M88.-) would be more appropriate.