This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Histiocytosis X is seen in except : 
Select and explain. 
A. Hand schuller Christian disease, B. Eosinophilic granuloma, C. Letter-siwe syndrome, D. Torres syndrome
D: Torres syndrome
Answer: D: Torres syndrome 
Explanation: Langerhans cell histiocytosis (Histiocytosis X) :

Histocytosis X is characterized by proliferation of Langerhans histiocytes (tissue macrophages).
It is subdivided into three categories : -


Letterer - Siwe syndrome.
Hand -Schuller-Christian disease.
Eosinophilic granuloma..


Tumor cells in each are derived from dendritic cells and express S - 100, CD1a and HLA - DR.
The presence of Birbeck granules in the cytoplasm is characteristic.
Under the electron microscope, Birbeck granules have a pentalaminar, rodlike, tubular appearance and sometimes a dilated terminal end (tennis - racket appearance).