An accumulation of mast cells in MS plaques and normal appearing white matter observed by histopathological analysis [9,10], an elevation of mast cell specific enzyme (tryptase) in the cerebrospinal fluid (CSF) of MS patients [11], and an increase of mast cell markers (FcεRI, tryptase and chymase) [12] show the implication of mast cells in the pathophysiology of MS. Here, CMA1 is linked to myeloid sarcoma.