Orthopedic Coding Alert

Question: The provider performs a level-three evaluation and management (E/M) service for an established patient. Encounter notes indicate that the patient suffers from a “solitary bone cyst, R ankle/foot.” What code should I report for this diagnosis?  Also, what is the difference between a solitary bone cyst and an aneurysmal bone cyst?

Missouri Subscriber

Answer: First, we’ll deal with the diagnosis code. You should report M85.471 (Solitary bone cyst, right ankle and foot) with your 99213 (Office or other outpatient visit for the evaluation and management of an established patient, which requires at least 2 of these 3 key components: An expanded problem focused history; An expanded problem focused examination; Medical decision making of low complexity …) claim to represent this patient’s cyst.

Now, a bit more about both types of bone cysts.

Solitary bone cyst: You’ll report solitary bone cysts with a code from the M85.4XX (Solitary bone cyst) set. “A solitary bone cyst of the right ankle and foot is a benign, empty or fluid filled, cavity in the bones that weakens the bones; also known as a simple bone cyst. A solitary bone cyst of the right ankle and foot may result in pain, weakness in the bones leading to bone fractures, restriction of motion, discoloration of the skin around the bone, bending of the affected part at an unusual angle, and or an inability to bear weight on the affected bone,” according to Codify.

If you’re in a pinch and are not sure if a diagnosis is a solitary bone cyst or not, rely on the above information for coding clues.

Aneurysmal bone cyst: You’ll report aneurysmal bone cysts with a code from the M85.5XX (Aneurysmal bone cyst) set. “Aneurysmal bone cyst is a benign lesion that occurs in the bones, consists of blood filled channels, and resembles a tumor. An aneurysmal bone cyst may result in localized pain, swelling, a lump or deformity in the bone, weakness in the affected body part, restriction of motion, and warmth of skin around the affected bone,” according to Codify.

If you’re in a pinch and are not sure if a diagnosis is an aneurysmal bone cyst or not, rely on the above information for coding clues.

Other/unspecified bone cyst: If you can’t get a ruling on which type of bone cyst your provider is dealing with, opt for the M85.6XX (Other cyst of bone) code set.