Mantle cell lymphoma (MCL) is an agressive B-cell lymphoma, constitutes 3-10% of all non-Hodgkin's lymphomas. MCL usually presents with generalized lymph node involvement. The prognosis is poor and incurable. Extranodal involvement is not uncommon, but central nervous system involvement is very rare. Herein, we present a case with isolated central nervous system relaps who achieved a complete response with ibrutinib treatment.

53yearold female patient diagnosed with MCL underwent autologous stemcelltransplantation after R-CHOPchemotherapy. While being followed up in complete remission, she presented with a complaint of headache. Parenchymal lesions in brain was observed in MRI.Cerebrospinal fluid flow cytometric and cytological examination revealed MCL-centralnervoussystem involvement. There was no finding in terms of systemic relaps.The patient was achieved complete response with ibrutinib and high dose methotrexate

Central nervous system involvement at the time of diagnosis in mantle cell lymphoma is very rare however it can be more common in relaps and generally is associated with advanced stage disease or is a part of systemic relaps. Our case is quite interesting as it presents with isolated central nervous system infiltration. In this case, our treatment choice was ibrutinib because of its satisfactory response rates and proven effectiveness on central nervous system.

The patient is currently being followed up with a complete response. It should be underlined that even in patients followed up with complete remission, symptoms such as headache, which can sometimes be subjective, should be approached sensitively, and it should not be forgotten that they may indicate an unexpected involvement of the disease.