IL21 and synovial sarcoma: Uncontrolled B-cell activation and aberrant somatic hypermutation22 within SS SG can lead to genetic instability and progression to parotid B-cell MALT-L in around 5% of patients with SS,4 suggesting that lymphomagenesis in SS is partially sustained by T-cell-driven responses, similarly to gastric MALT-L,31 32 although also extra follicular and T cell-independent mechanisms are key in neoplastic B cell expansion.4 Therefore, we assessed IL-21 production and Tfh-cells infiltration in SS parotids with MALT-L.