Case Report: Alectinib and CNS-directed therapy for primary or relapsed ALK-positive anaplastic large cell lymphoma with central nervous system involvement.

ALK-positive anaplastic large cell lymphoma (ALCL) is a rare T-cell lymphoma, typically associated with a favorable prognosis. However, outcomes in refractory or relapsed ALK-positive ALCL with central nervous system (CNS) involvement are poor, and no standard therapy has been established. Emerging data suggest that ALK inhibitors may be safe and effective for CNS ALK-positive ALCL. Here, we present two cases of ALK-positive ALCL with CNS involvement. The first patient, an 18-year-old male was diagnosed with ALK-positive ALCL and achieved complete remission after six cycles of chemotherapy and autologous hematopoietic stem cell transplantation (HSCT) but subsequently relapsed in the CNS. He received intrathecal chemotherapy and alectinib, followed by consolidation with allogeneic HSCT, and has remained in remission for over 81 months on alectinib maintenance. The second patient, a 31-year-old woman, presented with symptoms of meningitis and was diagnosed with ALK-positive ALCL with primary isolated CNS involvement. She received alectinib combined with CNS-directed chemotherapy and has remained in complete remission for 20 months on alectinib maintenance. These cases suggest that alectinib, combined with CNS-directed chemotherapy, is effective in both ALK-positive ALCL with CNS relapse and primary isolated CNS disease.