The diagnostic role of transbronchial lung cryobiopsy in inflammatory myeloid neoplasms

Inflammatory myeloid neoplasms(IMN), including Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD),may require histological confirmation. Surgical lung biopsy(SLB) is the traditional diagnostic standard but carries notable morbidity. Transbronchial lung cryobiopsy(TBLC) has emerged as a less invasive alternative, though its role in IMN remains insufficiently defined.

We retrospectively analyzed patients diagnosed with pulmonary IMN between 2014 and 2025 who underwent TBLC or SLB. Clinical, radiological, histopathological, and molecular data were collected. Diagnostic yield, complications, and feasibility of TBLC were compared with SLB. Semi-quantitative HRCT scoring was used to assess cystic and nodular burden and explore correlations with pulmonary function and pneumothorax risk.

Twenty-one patients underwent TBLC and seven underwent SLB. TBLC established a diagnosis in 17 of 21 cases(81%), while SLB was diagnostic in all seven. NGS was feasible in nine cryobiopsy samples, identifying MAPK-pathway mutations in three patients. Cystic burden correlated with reduced FEV₁ and showed a trend toward lower DLCO; nodular scores were higher in the TBLC group and associated with a significantly higher FEV₁/FVC ratio, suggesting earlier disease stages. Pneumothorax occurred in three PLCH patients (17%), all managed with chest tube placement. Although cystic scores were higher in these cases, no significant association was observed within the TBLC subgroup. Mean hospital stay after TBLC-related pneumothorax was shorter than that for SLB.

TBLC is a feasible and effective diagnostic approach for pulmonary IMN. Cystic burden reflects functional impairment and may influence procedural risk but does not preclude TBLC when guided by multidisciplinary evaluation.