ICD-10 Code K09.8 – Other cysts of oral region, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K09.8 – Other cysts of oral region, not elsewhere classified
What it is
K09.8 identifies cysts in the oral region that do not fit a more specific ICD-10 category. Use it for documented mouth or jaw cysts when the record does not name a more precise cyst type.
Clinical signs
Findings may include a localized, usually slow-growing swelling in the mouth or jaw area. Clinical features vary; refer to documentation, imaging, and the clinician’s description of the cyst.
When to use this code
Use K09.8 when the provider documents an oral-region cyst but does not identify it as a specific odontogenic or developmental cyst. It also fits when the chart states “other cyst” or gives only a nonspecific oral cyst diagnosis. If the lesion is better defined, code the more specific option instead.
Do not use for
Do not use this code for abscesses, tumors, or inflammatory lesions of the mouth. If documentation names a specific cyst type or a different site, choose that code instead.
Coding tip
Check the pathology, imaging, and final provider diagnosis before assigning K09.8.