Other cyst of bone, left upper arm

This code signifies the presence of a non-neoplastic, fluid-filled or semi-solid sac within the bone of the patient's left upper arm. These cysts are typically benign and can be asymptomatic or cause localized pain and swelling. They are distinct from bone tumors or infectious processes.

Apply this code when documentation clearly indicates a diagnosis of a bone cyst located specifically in the left humerus or other bone of the left upper arm. Supporting documentation would include imaging reports (X-ray, MRI) describing the lesion as a cyst, along with a physician's diagnostic statement.

• Ensure laterality is explicitly documented as "left upper arm" to support this specific code.
• Differentiate from bone tumors (e.g., osteochondroma, enchondroma) which have distinct coding.
• If the cyst is a solitary bone cyst (simple bone cyst), consider codes from the M85.5- category, ensuring correct laterality.