Osteitis deformans in neoplastic diseases, right lower leg

This code signifies Paget's disease of bone (osteitis deformans) occurring in the context of a neoplastic process, specifically affecting the right lower leg. It indicates bone remodeling abnormalities and increased bone turnover associated with a co-existing tumor.

Use this code when documentation clearly states a diagnosis of osteitis deformans in the right lower leg and explicitly links it to a neoplastic disease. This typically applies to patients with a known malignancy where Paget's disease is either a paraneoplastic manifestation or directly influenced by the tumor.

• Always code the underlying neoplastic disease first, followed by this code.
• Ensure documentation specifies "right lower leg" and the association with a neoplastic disease; otherwise, a more general Paget's code may be appropriate.
• Distinguish from Paget's disease of bone without a neoplastic association (M88.- series) and pathological fractures due to neoplasm (M84.5- series).