ICD-10 Code K09 – Cysts of oral region, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K09 – Cysts of oral region, not elsewhere classified
What it is
K09 identifies cysts arising in the oral region that are not classified elsewhere. Use it when the record documents an oral cyst but does not specify a more exact cyst type.
Clinical signs
These lesions may present as a localized swelling, a slow-growing oral mass, or an incidental radiographic finding. Clinical features vary; refer to documentation.
When to use this code
Use K09 when the provider documents a cyst of the mouth, jaw, or oral tissues and no more specific ICD-10-CM code applies. It is appropriate when the note clearly supports an oral-region cyst but lacks detail for a site-specific or named diagnosis. Check documentation if the lesion is described more precisely.
Do not use for
Do not use K09 for abscesses, tumors, or inflammatory lesions of the oral cavity. If the chart identifies a specific cyst type or a different anatomic category, code that diagnosis instead.
Coding tip
Review the pathology, imaging, and provider assessment to confirm the lesion is a cyst and not another oral mass.