Primary central nervous system ALK-negative anaplastic large cell lymphoma: a case report and literature review.

Primary central nervous system anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is an extremely rare type of primary central nervous system lymphoma (PCNSL). There are only nine cases reported in the literature to date, most of which have an overall survival time of no more than 8 months. Herein, we report such a rare case who has a good outcome with the longest survival time and perform a review of the literature. A 19-year-old male patient was admitted to the hospital complaining of dizziness. CT and MRI imaging showed a heterogeneous enhanced lesion in the left parieto-occipital lobe and the leptomeninges of the occipital lobe and the cerebellum. The lesion was resected and confirmed to be ALK-negative ALCL by pathological examination. Then, the patient received 10 cycles of chemotherapy with high-dose methotrexate (HD-MTX) and whole-brain radiotherapy. The patient recovered well and was regularly followed up. He was free of symptoms without recurrence on imaging examination 3 years later. ALCL is a rare type of PCNSL. HD-MTX combined with radiation is an effective therapeutic approach. However, further prospective studies with a large number of patients are needed to identify the biological characteristics of this rare type of PCNSL.