M85.669 is the authoritative medical code for Other cyst of bone, unspecified lower leg. This classification is used in medical billing and clinical recording to specify the clinical criteria for other cyst of bone, unspecified lower leg (ICD-10-CM M85.669), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Other cyst of bone, unspecified lower leg is a billable ICD-10-CM diagnosis code M85.669. Excludes1 (not coded here): cyst of jaw NEC M27.4; osteitis fibrosa cystica generalisata von Recklinghausen's disease of bone; osteogenesis imperfecta Q78.0; osteopetrosis Q78.2; osteopoikilosis Q78.8; polyostotic fibrous dysplasia Q78.1.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for M85.669 in the official ICD-10-CM tabular list.
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- cyst of jaw NEC M27.4
- osteitis fibrosa cystica generalisata von Recklinghausen's disease of bone
- osteogenesis imperfecta Q78.0
- osteopetrosis Q78.2
- osteopoikilosis Q78.8
- polyostotic fibrous dysplasia Q78.1
Frequently Asked Questions (FAQ) & Clinical Guidance
What can't be coded together with M85.669?
Per Excludes1 instructions, M85.669 must not be reported with: cyst of jaw NEC (M27.4); osteitis fibrosa cystica generalisata [von Recklinghausen's disease of bone] (E21.0); osteogenesis imperfecta (Q78.0); osteopetrosis (Q78.2).
Codes in This Family (40)
Official ICD-10-CM classifications in the same code family as M85.669, with their registry titles.
- M85 — Other disorders of bone density and structure
- M85.0 — Fibrous dysplasia (monostotic)
- M85.00 — Fibrous dysplasia (monostotic), unspecified site
- M85.01 — Fibrous dysplasia (monostotic), shoulder
- M85.011 — Fibrous dysplasia (monostotic), right shoulder
- M85.012 — Fibrous dysplasia (monostotic), left shoulder
- M85.019 — Fibrous dysplasia (monostotic), unspecified shoulder
- M85.02 — Fibrous dysplasia (monostotic), upper arm
- M85.021 — Fibrous dysplasia (monostotic), right upper arm
- M85.022 — Fibrous dysplasia (monostotic), left upper arm
- M85.029 — Fibrous dysplasia (monostotic), unspecified upper arm
- M85.03 — Fibrous dysplasia (monostotic), forearm
- M85.031 — Fibrous dysplasia (monostotic), right forearm
- M85.032 — Fibrous dysplasia (monostotic), left forearm
- M85.039 — Fibrous dysplasia (monostotic), unspecified forearm
- M85.04 — Fibrous dysplasia (monostotic), hand
- M85.041 — Fibrous dysplasia (monostotic), right hand
- M85.042 — Fibrous dysplasia (monostotic), left hand
- M85.049 — Fibrous dysplasia (monostotic), unspecified hand
- M85.05 — Fibrous dysplasia (monostotic), thigh
- M85.051 — Fibrous dysplasia (monostotic), right thigh
- M85.052 — Fibrous dysplasia (monostotic), left thigh
- M85.059 — Fibrous dysplasia (monostotic), unspecified thigh
- M85.06 — Fibrous dysplasia (monostotic), lower leg
- M85.061 — Fibrous dysplasia (monostotic), right lower leg
- M85.062 — Fibrous dysplasia (monostotic), left lower leg
- M85.069 — Fibrous dysplasia (monostotic), unspecified lower leg
- M85.07 — Fibrous dysplasia (monostotic), ankle and foot
- M85.071 — Fibrous dysplasia (monostotic), right ankle and foot
- M85.072 — Fibrous dysplasia (monostotic), left ankle and foot
- M85.079 — Fibrous dysplasia (monostotic), unspecified ankle and foot
- M85.08 — Fibrous dysplasia (monostotic), other site
- M85.09 — Fibrous dysplasia (monostotic), multiple sites
- M85.1 — Skeletal fluorosis
- M85.10 — Skeletal fluorosis, unspecified site
- M85.11 — Skeletal fluorosis, shoulder
- M85.111 — Skeletal fluorosis, right shoulder
- M85.112 — Skeletal fluorosis, left shoulder
- M85.119 — Skeletal fluorosis, unspecified shoulder
- M85.12 — Skeletal fluorosis, upper arm
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:
ICD Code M84.669
Pathological fracture in other disease, unspecified tibia and fibula
ICD Code M90.669
Osteitis deformans in neoplastic diseases, unspecified lower leg