Treatment of Unifocal Langerhans Cell Histiocytosis (Solitary Lesion) in Adults

Clinical Scenario

This protocol applies to an adult presenting with unifocal Langerhans cell histiocytosis — a single lesion involving any organ — without diabetes insipidus. The unifocal designation distinguishes this presentation from single-system multifocal disease, which involves more than one lesion.

Disease Classification & Initial Approach

For unifocal LCH without diabetes insipidus, observation or local therapies are the recommended first-line approach. When local management is not feasible or the disease has not responded, systemic chemotherapy becomes the appropriate next step. The full protocol details which systemic agents are preferred and the basis for selecting among them.

Treatment Goals

Response is evaluated using FDG-PET-based imaging, typically repeated after the first 2–3 months of therapy to assess reduction or normalisation of FDG-avid lesions. Subsequent imaging frequency is tailored to the individual clinical situation.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1182/blood.2021014343

The proposed classification system differentiates between unifocal (solitary lesion) and single-system multifocal disease (>1 lesion).

For unifocal LCH (except DI), observation or local therapies such as surgical excision, intralesional steroids, or radiation are recommended as first-line treatments.

For disease recurrence not amenable to local therapies or unresponsive to immunosuppressive agents, systemic chemotherapy is recommended.

For initially FDG PET avid LCH, it is recommended to repeat an FDG PET-based imaging study for assessment of disease response after 2-3 mo of initiation of therapy, with subsequent imaging frequency tailored individually based on the specific clinical scenario.

View source ↗