Abstract
Histiocytosis X is an idiopathic disease, characterized by a disorder of the reticulo-endothelial system in the human body. Histopathological studies carried out right from the 1800s have seen a significant similarity in the pathologic process of different stages in particular clinical syndromes showing proliferation of mature histiocytes. It was then modified by Lichenstein in 1953 as "Histiocytosis X". The exact aetiology is unknown; hence, the name "Histiocytosis X". The disease classically presents with three syndromes namely Eosinophilic granuloma, Letterer-Siwe disease and Hand-Schuller-Christian disease. These syndromes present with a spectrum of clinical manifestations with histiocytic proliferation in the granulomatous lesion. The disease is neither familial nor hereditary, nor does it have any microbiological pathologic origin. This disease can be conservatively managed by antibiotics and steroids or surgical curettage with radiotherapy. We report a five-year-old male child who was incidentally diagnosed to have Histiocytosis X. This patient was managed with a moderate surgical procedure with total avoidance of radiotherapy. An adequate follow-up of this patient shows total regression of the lesion and good bone healing.