Cytology of Langerhans cell histiocytosis in effusions : A case report

BACKGROUND: Langerhans cell histiocytosis is a relatively rare disorder of children, characterized by abnormal proliferation of Langerhans cells. There has been no report on the cytologic appearance of Langerhans cells in effusions. CASE: A 20-year-old had a 12-year history of the disease, since he was 8 years old. He had multiple mass lesions in the bones, lung and liver, and Langerhans cells appeared in the pleural fluid and ascites. They had indented, twisted or grooved nuclei, with a finely or coarsely granular chromatin pattern. Some of the nuclei were eccentrically located, and prominent nucleoli were occasionally seen. Immunohistochemically the cells showed positivity for S-100 protein. Electron microscopic examination revealed abortive Birbeck granules. CONCLUSION: The cytologic appearance was somewhat accentuated and different from that reported for other sites. Immunohistochemical staining for S-100 protein and/or electron microscopic examination should be employed.