PTGS2 and histiocytic sarcoma: While Desjardins et al. suggested the implication of COX-2 induction in the pathogenesis of HS in TLE [101], Weidner et al. found no difference in COX-2 expression between TLE with HS and TLE without HS groups implying COX-2 induction to be independent of presence/absence of HS [100].