Adoptive transfer of T cells modified to express chimeric antigen receptors (CARs) targeting CD19 (CART19s) has demonstrated impressive results in treating B-cell malignancies. Although CART19-induced complications have been gradually recognized, local cytokine-release syndrome (CRS) at particular parts of the body has not been extensively studied. In this paper, we firstly present a successfully treated case of severe dyspnea caused by the rapid enlargement of cervical lymph node following CART19 therapy in a relapsed/refractory DLBCL patient, with emphasis on the recognition, workup, and treatment. This report reminds for a careful evaluation and observation of the pre-existing mass, which could enlarge rapidly again as a result of CRS and be life threatening, in the CART therapy.