Smoking habit | Histology | Chest CT | Special techniques | Molecular abnormalities | |
LCH | Yes | Bronchiolocentric nodules with Langerhans cells, eosinophils and other inflammatory cells; multiple stellate-shaped nodules or fibrotic cysts separated by normal lung parenchyma | Bronchiolocentric nodules and/or fibrotic cysts with upper lobes involvement and sparing of costophrenic angles | S100+, CD1a+, Langerin+ factor XIIIa- Birbeck granules at electron microscopy | BRAF (V600E) mutations in ∼30% |
ECD | No | Expansion of pleura, interlobular septa and peribronchiolar tissue with xanthomatous/foamy histiocytes and interspersed inflammatory cells, multinucleate Touton-like giant cells in a fibrotic background | Thickening of pleura, interlobular septa and centrilobular nodules with/without pleural effusion and ground-glass opacities; mediastinal involvement | CD68+, CD163+, factor XIIIa+ CD1a-, S100-, Langerin- | BRAF (V600E) mutations in ≤60% |
RDD | No | Expansion of pleura, interlobular septa and peribronchiolar tissue by histiocytic cells with mixed inflammatory infiltrates and emperipolesis phenomenon | Diffuse lymphadenopathies; expansion of pleura, interlobular septa and bronchiolocentric tissue | CD68+, S100+, CD14+ and CD11c1 CD1a-, Langerin-, factor XIIIa- | No BRAF V600E mutation |
CT: computed tomography.