Flow cytometric DNA analysis of lesions from 18 children with langerhans cell histiocytosis (histiocytosis x).

The DNA content in 26 formalin-fixed, paraffin-embedded histologic specimens from 18 children with Langerhans cell histiocytosis (LCH) was analyzed by flow cytometry. In two cases, the propidium iodide fluorescence histograms showed small (5 and 3% of the analyzed nuclei) but significant aneuploid subpopulations with DNA indices of approximately 1.5. This was confirmed by analysis of unfixed, frozen material in one patient. Both patients had disseminated disease without organ dysfunction and were treated with prednisone. Currently, they are without signs of disease activity after 1 and 10 years. DNA histograms were normal from a patient who died from disseminated disease and from two patients with disseminated disease who experienced several relapses and various chemotherapeutical regimens. The histograms were also normal in lesions from four patients with unifocal bone involvement. Our results show that DNA aneuploidy occurs in LCH lesions in the pediatric age group. Further investigation is necessary to reveal whether DNA aneuploidy is restricted to disseminated LCH or its presence has any value in predicting the course and outcome of the disease.