[Langerhans cell histiocytosis: a clinicopathologic and immunohistochemical analysis of 258 cases].

Objectives: To observe the clinicopathologic features of Langerhans cell histiocytosis (LCH), and to evaluate the values of langerin, CD1a and S-100 protein expression in diagnosis of the tumor.

Methods: Total 258 cases of Langerhans cell histiocytosis in the past 18 years (from 1992 to 2008) were collected, morphologic review and immunohistochemical staining were performed.

Results: In all 258 cases, the ages of patients older than 16 years or younger than 2 years were 126 (48.8%) and 37 (14.3%), respectively, in the remaining 95 (36.8%) of the cases, the age of the patients ranged from 2 to 16 years. For all of 258 cases, there were 364 diseased sites. Bony lesions accounted for 77.2% (281 cases), especially the skull (112 cases, 39.9%), followed by lymph node (25 cases, 6.9%) and skin (14 cases, 3.8%). Clinically, unisystem or unifocal disease was predominant (201 cases, 77.9%), followed by unisystem and multifocal disease (21 cases, 8.1%), multi-system disease (26 cases, 10.1%), isolated pulmonary LCH (2 cases, 0.8%), and unclassified (8 cases, 3.1%). Histologically, variable number of Langerhans cells was present in 265 samples of 258 cases. Multinucleated giant cells were found in 166 (62.6%) of the samples. Eosinophils were the major infiltrating non-neoplastic cells, and eosinophilic abscess was seen in 57 cases (21.5%). Coagulative necrosis and dead bone were detected in 29 (10.9%) and 124 (46.8%) of the cases, respectively. Immunohistochemically, the expression of S-100 protein, CD1a and langerin was 99.1% (209/211), 100% (206/206) and 98.5% (193/196), respectively, and the sensitivity of them had no statistical difference.

Conclusions: In this group of LCH cases, the ratio of adult patients is high, but the proportion of multi-organ lesion is low. No significant difference of the sensitivity is found among langerin, CD1a and S-100 expression in diagnosis of LCH.