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ICD-10-CM 2027 diagnosis code

K09Cysts of oral region, not elsewhere classified

Not billable — use a more specific code

K09 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About K09

K09 is the ICD-10-CM diagnosis code for cysts of oral region, not elsewhere classified. It belongs to block K00-K14 (diseases of oral cavity and salivary glands) and chapter 11 (diseases of the digestive system). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: K09.0 (cysts), K09.1 (region), K09.8 (classified) and K09.9 (unspecified).

The conditions in its Excludes2 note aren't part of K09, but may be coded alongside it if the patient has both: cysts of jaw (M27.0-, M27.4-) and radicular cyst (K04.8).

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

Specific codes under K09

Coding notes

IncludesFurther defines the content of the category
  • lesions showing histological features both of aneurysmal cyst and of another fibro-osseous lesion
Excludes2Not included here — may be reported together if both conditions exist

Notes that apply from higher levels

Instructions written at a parent level also apply to K09.

Broader instructions also apply from Chapter 11: Diseases of the digestive system.

Codes whose notes reference K09

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about K09

Is K09 billable?

No. K09 is a header code. Report one of its more specific subcodes instead.