Histiocytosis-X is a rare disease presenting as 3 clinical syndromes; eosinophilic granuloma, H and-Schüller-Christian disease, Letterer-Siwe disease. Although the clinical expressions of the disease differ, the underlying histopathology appears to be the same. Our patient was a 3-year-old boy with a recurrent neck tumor, who had been treated for left temporal bone eosinophilic granuloma about one year earlier. Our diagnosis was a Hand-Schüller-Christian disease developing from an eosinophilic granuloma, but it was not typical. The pertinent literature on the signs, symptoms, diagnosis, and treatment of this disease is reviewed.
