M85.571 (Aneurysmal bone cyst, right ankle and foot) compared with M85.579 (Aneurysmal bone cyst, unspecified ankle and foot), from the official CMS tabular data. M85.571 and M85.579 code the same condition on opposite sides. MedCoder-derived
Same condition; these differ only in which side is documented.
These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.
Source: ICD-10-CM tabular list (laterality variant derived from the code title)
Same condition, opposite side. M85.571 and M85.579 name the same condition on opposite sides of the body.
Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.
| M85.571Aneurysmal bone cyst, right ankle and foot | M85.579Aneurysmal bone cyst, unspecified ankle and foot | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the musculoskeletal system and connective tissue | M00-M99 — Diseases of the musculoskeletal system and connective tissue |
| Definition | Aneurysmal bone cyst, right ankle and foot is a billable ICD-10-CM diagnosis code (M85.571). | Aneurysmal bone cyst, unspecified ankle and foot is a billable ICD-10-CM diagnosis code (M85.579). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources