EBV-positive PEL-like lymphoma that developed in the course of antisynthetase syndrome treated with tacrolimus

Primary effusion lymphoma (PEL) is a rare type of extranodal lymphoma, typically of a B-cell origin, which presents as lymphomatous effusion with no nodal enlargement or tumor masses. The development PEL is universally associated with human herpes virus-8 (HHV-8) infection. Cases of HHV-8-negative primary lymphomatous effusion have recently been reported and referred to as HHV-8-unrelated PEL-like lymphoma. Some cases of this disease have been reported in iatrogenic immunocompromised patients. The mechanisms responsible for the inhibitory effects of the discontinuation of immunosuppressants other than methotrexate (MTX) against the disease, which have been demonstrated for MTX-associated lymphoproliferative disorders, have not yet been elucidated. We describe a case of PEL-like lymphoma that developed in the course of antisynthetase syndrome and was treated with tacrolimus. A single dose of systemic chemotherapy did not improve lymphomatous effusion, whereas the discontinuation of tacrolimus resulted in the long-term remission of this disease.