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: Pathology
Which of the following is not a type of langerhans cell histiocytosis? 
Select and explain. 
A. Hand Schuller Christian disease, B. Eosinophilic granuloma, C. Letter-siwe syndrome, D. Tones syndrome
D: Tones syndrome
Answer: D: Tones syndrome 
Explanation: Ans. is `d.' i.e., Torres syndrome Langerhans cell histiocvtosis (Histiocytosis X) Histiocytosis 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, CD la and HLA-DR. The presence of Birbeck granules in the cytoplasm is characteristic. Under electron microscope, Birbeck granules have a pentalaminar, rod like, tubular appearance and sometimes a dilated terminal end (tennis-rachet appearance).