Single-System Pulmonary LCH in Adult Smokers When First-Line Therapy Does Not Achieve Complete Remission

Single-system pulmonary Langerhans cell histiocytosis (PLCH) with isolated lung involvement in an adult smoker is predominantly a smoking-related condition. When initial management — built around complete substance cessation — does not produce the expected remission, a structured next-step approach is needed.

Clinical Scenario

Isolated lung involvement in an adult smoker. Cessation of smoking, vaping, and inhalation of marijuana or other substances is established as the foundation of first-line therapy for single-system PLCH.

First-Line Therapy — Failure Condition

The prior management step — cessation of smoking, vaping, and all inhaled substances, together with combined inhaled corticosteroid plus long-acting β₂-agonist therapy where indicated for wheezing and moderate obstructive disease — did not achieve complete remission of pulmonary LCH on pulmonary function tests and HRCT chest at 3–6 months.

This non-achievement of the remission target is the threshold for escalation to the next treatment line.

Next-Step Approach (Partial Overview)

For progressive single-system PLCH — or stable disease with clinically significant respiratory symptoms or dysfunction — systemic therapy is recommended. A preferred systemic agent is identified for this setting; the full protocol covers agent selection, sequencing, and monitoring.

The primary treatment goal is improved lung function on pulmonary function tests.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1182/blood.2021014343

Single-system pulmonary | Isolated lung involvement (predominantly smoking related).

Cessation of smoking, vaping, inhalation of marijuana or other substances is recommended as first-line therapy for single-system PLCH.

Systemic therapy is recommended for single-system PLCH in the presence of progressive disease (regardless of smoking status) or for stable disease with clinically significant respiratory symptoms or dysfunction.

Cladribine (2-chlorodeoxyadenosine) use was associated with improved lung function in multiple studies and is the preferred systemic therapy.

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