Osteitis deformans in neoplastic diseases, left upper arm

This code signifies Paget's disease of bone (osteitis deformans) occurring as a manifestation or complication of a neoplastic process, specifically affecting the patient's left upper arm. It indicates a secondary bone condition directly linked to an underlying malignancy, not a primary bone tumor.

Apply this code when documentation clearly states osteitis deformans in the left upper arm and explicitly links it to a neoplastic disease. This typically occurs in patients with known cancer where Paget's disease is identified as a paraneoplastic syndrome or a direct effect of tumor invasion or metastasis. Supporting documentation includes pathology reports, imaging studies (e.g., bone scan, X-ray), and physician notes detailing the causal relationship.

• Always sequence the underlying neoplastic disease code first, as this condition is a manifestation of the neoplasm.
• Ensure the documentation specifies "left upper arm" to justify the laterality and anatomical site.
• Differentiate from primary Paget's disease (M88.-) which is not associated with a neoplastic process.