Histiocytosis X is seen in except - (AIIMS Nov 2014)
|A||Hand schuller Christian disease|
Langerhsns cell histiocytosis (Histiocytosis X)
oHistocltosis X is characterized by proliferation of langerhanshistiocytes (tissue macrophages).
o It is subdivided into three categories : -
i) Letterer - Siwe syndrome
i) Hand –Schuller - Chrtstian disease
iii) Eosinophilic granuloma
oTumor cells in each are derived from dendritic cells and express S-I00, CD1a and HLA-DR
o The presence of Birbeck granules in the cloplasm is characteristic.
o Under the electron microscope, Birbeck granules have a pentalaminar, rodlike, tubular apperance and sometimes a dilated terminal end (tennis - racket appearance).