JXG was first reported in 1905 by Adamson, who described a 2-year-old boy with multiple yellow cutaneous papules that eventually regressed spontaneously.
The etiology and pathogenesis of JXG are still unclear.
The histopathologic hallmark of JXG is the Touton giant cell, a multinucleated giant histiocyte whose rings of nuclei separate a central homogeneous core from a foamy periphery.
The diagnosis was made by histolo-gical examination showing in the left eye proliferated histiocytosis and infiltration of plasma cells and lymphocytes in a special pattern of emperipolesis doing the diagnosis of RDD (figure 2), and in the right eye a similar pattern with foamy histiocytes but without emperipolesis such as JXG. On immunohistochemical staining histiocytes were reactive for S-100 and CD68 proteins in RDD but just reactive for CD68 in JXG (figure 3).
The Histiocytes International Society classifies the histiocytosis in three large groups: Langerhans' cells histiocytosis, monocytes/macrophages cells histiocytosis different from Langerhans' cells (among them the RDD and JXG) and the harmful histiocytic disorders.
The sinus histiocytosis with massive lymphadenopathy (SHML) or RDD is a rare histiocytic disorder of unknown origin which shares several cell markers with JXG. Although Rosai-Dorfman cells exhibit an aberrant immunophenotype, the indolent clinical course of SHML suggests a reactive disorder rather than a neoplastic process.
The clinical differential diagnosis for JXG includes dermatofibromas, Langerhans cell histiocytosis, mastocytosis.
There are no systemic tests that can be used to determine if a cutaneous lesion is JXG. Thus, biopsy is the gold standard diagnostic for confirmatory testing.
In conclusion, JXG is typically a benign, cutaneous disease.
Juvenile xanthogranuloma (JXG) is a benign, nonLangerhans cell histiocytic lesion that is most commonly found in or on the skin of the head, neck, or trunk.
To the best of our knowledge, no case of JXG of the tympanic membrane has been previously reported in the literature.
Subsequent immunohistochemical staining was positive for CD68 (figure 2, B) and negative for CDla, which helped clinch the diagnosis of JXG. No skin lesions or cafe au lair spots were found on physical examination, and the patient's family history was negative for anycutaneous skin disorders.