Table 1.
Summary of the classification, pathological, and radiological features of the histiocytic neoplasms.
| Disease | LCH | ECD | JXG/AXG | RDD | ICH |
|---|---|---|---|---|---|
| Broad classification | LCH | Non-LCH | Non-LCH | Non-LCH | Non-LCH |
| Revised classification groupings | L | L | L (extracutaneous) and C (cutaneous) | C (cutaneous) and R (other RDD) | L |
| Immunophenotypic features | |||||
| CD68 | + | ++ | ++ | ++ | + |
| CD163 | − | ++ | ++ | ++ | − |
| CD14 | − | ++ | ++ | ++ | − |
| CD1a | ++ | − | − | − | ++ |
| CD207 (Langerin) | ++ | − | − | − | − |
| S100 | + | −/+ | −/+ | + | + |
| Factor XIIIa | − | + | + | + | − |
| CD45 | + | + | + | + | + |
| Histological features | |||||
| Birbeck granules | Yes | No | No | No | No |
| Xanthomatous histiocytes | No | Yes | Yes | No | No |
| Touton giant cells | No | Yes | Yes | No | No |
| Emperipolesis (intractyoplasmic lymphocytes) | No | Occasional | Occasional | Abundant | No |
| Radiological features | |||||
| Bilateral, symmetric osteosclerosis involving metadiaphysis of femur, tibia, and fibula | Rare | Frequent, pathognomonic | No | No | No |
| Lytic, “punched-out” lesions of skull and axial skeleton | Frequent | Rare | No | No | No |
| Infiltrative, perinephric soft tissue thickening (“hairy kidney”) | No | Frequent | Rare | No | No |
LCH, Langerhans cell histiocytosis; ECD, Erdheim−Chester disease; JXG, juvenile xanthogranuloma; AXG, adult xanthogranuloma; RDD, Rosai−Dorfman−Destombes disease; ICH, indeterminate cell histiocytosis; L group, Langerhansrelated; C group, cutaneous and mucocutaneous; R group, Rosai−Dorfman−Destombes disease; +, low expression; ++, high expression; −, no expression.