Aneurysmal bone cyst, unspecified hand

This code identifies a benign, expansile, and lytic bone lesion characterized by blood-filled spaces separated by fibrous septa, occurring in an unspecified bone of the hand. It represents a non-neoplastic, osteolytic process that can cause pain, swelling, and pathological fractures.

Apply this code when documentation confirms an aneurysmal bone cyst located in any bone of the hand (e.g., metacarpal, phalanx) without further specification of the exact bone or laterality. This diagnosis is typically established through imaging studies (X-ray, MRI) and often confirmed by biopsy.

• Ensure the documentation explicitly states "aneurysmal bone cyst" and specifies the hand as the location.
• Avoid using this code if a more specific anatomical site within the hand (e.g., "right third metacarpal") is documented; instead, use a more precise code from the M85.54- series.
• Do not confuse with other benign bone tumors or cysts, such as unicameral bone cysts (M85.6-) or fibrous dysplasia (M85.0-).