TNF and myeloid sarcoma: Although it is now well established that insulin resistance (IR) represents the pathophysiological hallmark of MS [9], the mechanism leading to IR/MS in PsA patients is only partially explained by the abnormal metabolic phenotype [10] and could be accounted for also by the negative impact of TNF-α and other inflammatory cytokines on insulin signaling [11] and altered balance in adipocytokines [12].