Other cyst of bone, unspecified upper arm

This code represents a non-neoplastic, fluid-filled or semi-solid sac within the bone of the upper arm, the specific type of cyst not being further identified. These are typically benign lesions that may be discovered incidentally or due to pain or pathological fracture.

Use this code when documentation specifies an "other cyst of bone" located in the upper arm, and the specific type of cyst (e.g., aneurysmal, unicameral) is not documented or is unknown. This code is appropriate when imaging reports (X-ray, MRI) identify a bone cyst in the humerus without further characterization.

• Ensure the documentation clearly specifies the upper arm as the location; avoid using for other bone locations.
• If a more specific type of bone cyst is identified (e.g., unicameral bone cyst), use the appropriate, more specific code from the M85.6- category.
• Always review imaging reports and physician notes for precise anatomical location and cyst type to ensure the most specific code is selected.