ICD-10 Code C96.5 – Multifocal and unisystemic Langerhans-cell histiocytosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C96.5 – Multifocal and unisystemic Langerhans-cell histiocytosis
What it is
C96.5 identifies multifocal and unisystemic Langerhans-cell histiocytosis, a disorder involving abnormal Langerhans cells in one organ system with more than one site. Use this code when documentation confirms this specific pattern.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include lesions or dysfunction limited to one system, with involvement at multiple sites rather than widespread multisystem disease.
When to use this code
Use C96.5 when the provider documents Langerhans-cell histiocytosis affecting a single organ system at multiple locations. It is appropriate when the record clearly distinguishes this from multisystem disease or isolated single-site disease. Check documentation if the extent is unclear.
Do not use for
Do not use this code for multisystem Langerhans-cell histiocytosis, single-site disease, or unspecified histiocytosis. If the chart does not confirm multifocal unisystemic involvement, code only what is documented.
Coding tip
Confirm both the number of sites and that only one system is involved before assigning C96.5.