MKI67 and mantle cell lymphoma: CNS involvement in MCL is around 4%; however, the incidence at presentation is less than 1%.12,13 Bedotto et al first reported CNS infiltration in MCL in 1986.14 High MIPI score, B-symptoms, increased serum lactate dehydrogenase, blastoid variant, high Ki-67, bone marrow involvement, as well as poor performance status are possible risk factors for CNS involvement.12,13 Patients with CNS involvement should undergo CSF assessment for cytology and flow cytometry.