Solitary bone cyst, other site

This code signifies the presence of a single, benign, fluid-filled lesion within a bone, excluding those found in the humerus, tibia, or femur. These cysts are typically asymptomatic and often discovered incidentally on imaging studies. They are non-neoplastic and represent a localized area of bone resorption and fibrous tissue replacement.

Assign this code when documentation specifies a solitary bone cyst located in any bone other than the humerus, tibia, or femur. This includes cysts found in the fibula, ulna, radius, vertebrae, or small bones of the hands and feet. Supporting documentation would include imaging reports (X-ray, MRI, CT) confirming the presence and solitary nature of the cyst, along with its specific anatomical location.

• Ensure the documentation explicitly states "solitary" and specifies a site other than the humerus, tibia, or femur.
• Do not use this code for aneurysmal bone cysts or other types of bone cysts; specific codes exist for those conditions.
• If the cyst is located in the humerus, tibia, or femur, refer to the more specific codes within the M85.4 category.