Osteitis deformans in neoplastic diseases, unspecified hand

This code signifies Paget's disease of bone (osteitis deformans) occurring as a manifestation within the context of a neoplastic disease process, specifically affecting an unspecified hand. It indicates the presence of abnormal bone remodeling and enlargement in the hand, secondary to a co-existing cancer.

Apply this code when documentation clearly links Paget's disease of the hand to an underlying neoplastic condition. This would typically be supported by imaging studies confirming Paget's changes in the hand and a confirmed diagnosis of a primary or metastatic malignancy. Use when the specific hand (left or right) is not documented.

• Always sequence the underlying neoplastic disease code first, as M90.649 is a manifestation code.
• Ensure documentation specifies "osteitis deformans" or "Paget's disease" and a clear association with a neoplastic process.
• Avoid using this code if the Paget's disease is not explicitly stated as being related to a neoplastic condition; instead, use a code from M88.- for primary Paget's disease.