Pulmonary Langerhans Cell Histiocytosis
Definition
- Multinodular lung infiltrates of Langerhans cells
Alternate/Historical Names
- Eosinophilic granuloma
- Histiocytosis X
Diagnostic Criteria
- Includes all cases in which the lung is the principal site of involvement
- Approximately 10-15% of cases also involve other sites
- Primarily bone
- Systemic disease in which lung involvement is not dominant is not covered here
- Usually seen in children
- Predominantly pulmonary disease may be seen in children, but is rare
- Approximately 10-15% of cases also involve other sites
- Clinical
- Virtually all are smokers
- Presentation ranges from asymptomatic to rapidly progressive
- Usually dyspnea, occasionally fevers, pneumothorax
- Variable outcomes
- Spontaneous remission
- Remission following cessation of smoking
- Progression to end stage fibrosis
- High resolution computed tomography
- Centrilobular/peribronchiolar reticulonodular infiltrates
- Nodules 1-15 mm
- Diffusely scattered, primarily upper and mid lung fields
- Frequently forms patchy or diffuse cysts
- 1-3 mm, may be irregular
- If clinical and radiographic findings are classic, biopsy confirmation may not be necessary
- Centrilobular/peribronchiolar reticulonodular infiltrates
- Pathology
- Multiple centrilobular, discrete nodular infiltrates
- Peribronchiolar with stellate extension into surrounding alveolar walls
- Intervening lung tissue is normal
- Composed of Langerhans cells
- Uniform, bland nuclei
- Pale chromatin, thin nuclear membrane, inconspicuous nucleoli
- Characteristic folded, grooved nucleus
- Moderate amount of pale eosinophilic cytoplasm
- Positive for S100, CD1a, langerin
- Uniform, bland nuclei
- Infiltrate frequently also contains eosinophils
- May also contain lymphocytes, plasma cells, histiocytes and neutrophils
- Intra-alveolar organizing pneumonia frequently seen at periphery of nodules
- Intra-lumenal macrophages may be prominent in alveoli adjacent to nodule
- Not a diffuse finding
- Peribronchiolar with stellate extension into surrounding alveolar walls
- Nodules frequently cavitate, leading to cyst formation
- Increasing fibrosis with time leads to characteristic centrilobular stellate scars
- Infiltrate decreases, ultimately leading to scars with few or no Langerhans cells
- If bronchiole is obliterated, recognize by location adjacent to terminal arteriole
- Merging of scars and confluent cysts may lead to honeycomb change
- Although rare in children, pediatric cases are not infrequently associated with hematolymphoid or solid neoplasms
- In adults it has been reported associated with lymphoma and rarely carcinoma
- Multiple centrilobular, discrete nodular infiltrates
Gerald J Berry MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
