Disorders of bone density and structure

M84.80 identifies a disorder of bone continuity that falls outside more specific fracture or bone-density subcategories and cannot be assigned to a named anatomic site.

M84.88 captures non-traumatic disorders that disrupt bone structural continuity at sites not classified elsewhere in the M84.8 subcategory — most notably mandibular continuity defects and other craniofacial or axially atypical bone continuity pathology.

Monostotic fibrous dysplasia affecting a single bone whose anatomical site is not specified in the documentation — use only when the affected bone cannot be identified from the record.

Monostotic fibrous dysplasia affecting a skeletal site not captured by the more specific M85.01–M85.07 site codes — includes bones such as the ribs, skull base, pelvis, clavicle, scapula, or sternum when the lesion is confined to a single bone.

Monostotic fibrous dysplasia affecting more than one anatomical site simultaneously, where normal bone is replaced by fibrous connective tissue containing abnormal woven bone — but without the generalized polyostotic pattern of Q78.1.

Skeletal fluorosis affecting an unspecified anatomical site — a metabolic bone disorder caused by chronic excessive fluoride accumulation that leads to increased but structurally abnormal bone density, ligament calcification, and progressive joint stiffness.

M85.18 identifies skeletal fluorosis occurring at a site not captured by any other specific M85.1x subcategory — meaning a location other than the skull, shoulder, upper arm, forearm, hand, thigh, lower leg, or ankle/foot.

Skeletal fluorosis affecting two or more distinct anatomical sites simultaneously, classified under disorders of bone density and structure.

Osteitis condensans at an unspecified anatomical site — a benign condition characterized by sclerotic bone density changes, most commonly occurring at the ilium adjacent to the sacroiliac joint or at the pubic symphysis, without documented laterality or specific site.

Osteitis condensans affecting a skeletal site not captured by any laterality-specific subcategory within the M85.3x series — a benign sclerotic bone condition documented at an atypical or otherwise unclassified anatomical location.

Osteitis condensans affecting two or more distinct skeletal sites simultaneously, classified under other disorders of bone density and structure (M85 category).

M85.40 identifies a solitary bone cyst at an unspecified skeletal site — a benign, fluid-filled unilocular lytic lesion with well-defined endosteal margins, reported when the operative or imaging report does not specify which bone is affected.

M85.48 identifies a solitary bone cyst occurring at an anatomical site not captured by any other specific M85.4x subcode — a true 'other site' residual category within the solitary bone cyst family.

M85.50 identifies an aneurysmal bone cyst when the affected skeletal site is not documented or cannot be specified — a benign but locally destructive blood-filled fibrous lesion of bone capable of causing deformity and pathologic fracture.

M85.58 designates an aneurysmal bone cyst occurring at a skeletal site not captured by any other specific subcategory within M85.5 — such as the ribs, sternum, pelvis, or skull — where a blood-filled, expansile lesion disrupts normal bone architecture.

Aneurysmal bone cyst (ABC) involving two or more distinct skeletal sites simultaneously, coded under the M85.5 family of bone density and structure disorders.

M85.60 classifies a bone cyst that does not fit the solitary (unicameral) or aneurysmal categories, at an anatomic site that is not specified in the documentation.

M85.68 classifies a bone cyst of the 'other cyst of bone' type occurring at a site that has no dedicated lateralized subcode — including the skull, ribs, vertebrae, neck, and any other skeletal site not captured by M85.60–M85.67 or M85.69.

Other cyst of bone affecting multiple anatomical sites simultaneously, not classifiable to a single skeletal location.

M85.80 captures other specified disorders of bone density and structure — most commonly osteopenia — when the affected anatomical site is not documented or is truly generalized with no single site identified.

M85.88 classifies other specified disorders of bone density and structure occurring at a skeletal site not captured by the more granular M85.8x lateralized codes — commonly used for single-site osteopenia of the spine, hip, or forearm.

M85.89 identifies a named, non-osteoporotic disorder of bone density or bone structure that affects two or more distinct anatomical sites simultaneously — most commonly coded for multifocal osteopenia confirmed on DEXA.

Age-related (primary) osteoporosis documented without any currently active pathological fracture. Covers postmenopausal, senile, and involutional osteoporosis when no fracture is present at the time of coding.

M81.6 identifies localized osteoporosis of the Lequesne type — a regionally confined reduction in bone mineral density without a current pathological fracture, distinct from systemic age-related or drug-induced osteoporosis.

M81.8 captures osteoporosis without a current pathological fracture when the etiology is something other than age-related bone loss — including drug-induced, idiopathic, disuse, post-oophorectomy, postsurgical malabsorption, and post-traumatic causes.

Bone-softening disorder caused by defective mineralization that develops in the context of the postpartum (puerperal) period, typically driven by calcium and vitamin D depletion from pregnancy and lactation.

Senile osteomalacia is age-related softening of bone in adults due to defective mineralization, classified under adult osteomalacia (M83) in ICD-10-CM Chapter 13.

Softening of bone in adults caused by impaired nutrient absorption in the gastrointestinal tract, including postsurgical malabsorption states, leading to deficient mineralization.

Softening of bone in adults caused by insufficient dietary intake of nutrients essential for bone mineralization, most commonly calcium or vitamin D from food sources rather than malabsorption or metabolic disease.

M83.4 identifies aluminum bone disease, a form of adult osteomalacia caused by aluminum accumulation in bone tissue, typically seen in patients with chronic renal failure who have been exposed to aluminum-containing phosphate binders or aluminum-contaminated dialysate.

Adult osteomalacia caused by a drug or medication other than aluminum-containing compounds, resulting in defective bone mineralization in a skeletally mature patient.

Billable code for adult osteomalacia that does not fit any of the more specific M83 subcategories — covering etiologies such as vitamin D deficiency with adult osteomalacia (avitaminosis D), craniotabes of unknown cause, and other documented but uncategorized causes of defective bone mineralization in patients aged 15 and older.

Adult osteomalacia with no documented etiology or subtype — use when the provider diagnosis of osteomalacia is confirmed but the underlying cause has not been specified in the medical record.

M84.9 classifies a disruption or defect in bone continuity when the clinical record lacks sufficient detail to assign a more specific code within the M84 category.

M85.2 identifies abnormal thickening and overgrowth of the cranial bones (skull hyperostosis) classified under disorders of bone density and structure — not a congenital dysplasia or neoplasm.

Unspecified abnormality of bone density or structural integrity where documentation does not identify the specific disorder type or anatomical site.