Histiocytosis X comprises of a group of diseases characterized by the proliferation of histiocytes in the bone, three of the below mentioned are clinical entities of histiocytosis X, the exception is (AIPG 2012)
|B||Hand Schuller Christian disease|
|C||Utterer Siwe disease|
|D||Pellegrini Stieda disease|
Pellegrini Stieda disease
a. Eosinophilic granuloma is a solitary bone lesion commonly seen in femur, Hand Schuller Christian disease is a variant where the lesions are found at multiple sites.
b. Utterer Siwe disease is the most severe form with involvement of multiple bones it begins in childhood and rapidly progresses to death