A two-year-old boy had an extensive facial eruption of juvenile xanthogranuloma. The lesions were atypical clinically and histologically and were of 21 months' duration. Although biopsies obtained at the ages of 19 and 20 months suggested a diagnosis of histiocytosis X, his benign course, unremarkable physical examination, and normal findings from laboratory investigations favored a less ominous process. A third skin biopsy showed a dermal infiltrate composed of large, foamy cells and a moderate number of Touton giant cells. On electron microscopy the macrophages contained numerous lysosomes, myelin figures, altered mitochondria, and lipid droplets lacking a limiting membrane consisting with the findings in a previous study of juvenile xanthogranuloma. Langerhans' granules characteristic of histiocytosis X were absent.
Esterly NB, Sahihi T, Medenica M. Juvenile XanthogranulomaAn Atypical Case With Study of Ultrastructure. Arch Dermatol. 1972;105(1):99-102. doi:10.1001/archderm.1972.01620040067017