ICD-10 Code C96.6 – Unifocal Langerhans-cell histiocytosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C96.6 – Unifocal Langerhans-cell histiocytosis
What it is
C96.6 identifies Langerhans-cell histiocytosis limited to a single site. Use it when documentation shows one focal lesion rather than multisystem or multifocal disease.
Clinical signs
Clinical features vary; refer to documentation. Commonly, the record describes a solitary bone, skin, or soft-tissue lesion with pathology confirming Langerhans-cell histiocytosis.
When to use this code
Use C96.6 when the provider documents unifocal disease and the record supports one involved anatomic site. It is appropriate for confirmed Langerhans-cell histiocytosis limited to a single lesion, even if the workup includes imaging or biopsy.
Do not infer unifocal disease from partial notes. If the chart suggests multiple sites, systemic involvement, or uncertain extent, check documentation before assigning this code.
Do not use for
Do not use C96.6 for multifocal or multisystem Langerhans-cell histiocytosis. Also avoid it when the diagnosis is only suspected or when documentation does not confirm a single site.
Coding tip
Confirm both the diagnosis and the number of involved sites in the provider note before coding C96.6.