M85.6Other cyst of bone

M85.6 is the ICD-10-CM diagnosis code for other cyst of bone. It belongs to category M85 (other disorders of bone density and structure), block M80-M85 (disorders of bone density and structure) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 10 subcodes must be used instead.

Within M85, choose M85.6 (Other cyst of bone) only when documentation doesn't support a more specific option: fibrous dysplasia (monostotic) (M85.0), skeletal fluorosis (M85.1), hyperostosis of skull (M85.2), Osteitis condensans (M85.3), Solitary bone cyst (M85.4), Aneurysmal bone cyst (M85.5), other specified disorders of bone density and structure (M85.8) and disorder of bone density and structure, unspecified (M85.9).

To report this condition, pick the subcode that matches the documentation: M85.60 (unspecified site), M85.61 (shoulder), M85.62 (upper arm), M85.63 (forearm), M85.64 (hand), M85.65 (thigh), M85.66 (lower leg), M85.67 (ankle and foot) and 2 more.

Don't report M85.6 together with the conditions in its Excludes1 note: cyst of jaw NEC (M27.4) and osteitis fibrosa cystica generalisata [von Recklinghausen's disease of bone] (E21.0).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.