Solitary bone cyst, left tibia and fibula

This code identifies a benign, fluid-filled lesion occurring as a single entity within the bone structure of the left lower leg. These cysts are typically asymptomatic but can weaken the bone, leading to pathological fractures. They are often discovered incidentally on imaging.

Apply this code when documentation confirms a solitary bone cyst located specifically in the left tibia and/or fibula. This diagnosis is typically supported by imaging studies such as X-rays, MRI, or CT scans, which characterize the lesion as a simple, unilocular cyst. Use for both initial diagnosis and subsequent encounters related to the cyst.

• Ensure laterality is clearly documented as "left" for both tibia and fibula.
• Distinguish from aneurysmal bone cysts (M85.5-) or other bone tumors.
• If a pathological fracture is present due to the cyst, code the fracture first, followed by this code as an underlying condition.