A case of primary central nervous system anaplastic lymphoma kinase-positive anaplastic large cell lymphoma in the neurohypophysis and pineal gland

Most primary central nervous system lymphomas (PCNSLs) are diffuse large B-cell lymphomas (DLBCLs). Anaplastic large cell lymphoma (ALCL), which is a T-cell tumor, is a rare type of PCNSL. ALCLs are divided into two groups: anaplastic lymphoma kinase (ALK)-positive and ALK-negative. We report the case of a 26-year-old woman who presented with a 1-month history of headache and nausea. Magnetic resonance image (MRI) showed tumors in the neurohypophysis and pineal gland. These tumors were diagnosed as ALK-positive ALCL following an endoscopic brain biopsy. She underwent chemotherapy that included methotrexate, cyclophosphamide, doxorubicin, vincristine, and prednisolone. Follow-up contrast-enhanced MRI shows the complete response (CR) to chemotherapy. In previous reports, most ALK-positive ALCLs occurred in the cerebral hemisphere and dura mater. To our knowledge, no case of an ALK-positive ALCL that occurred in the neurohypophysis and pineal gland has been reported. It is necessary to accumulate more cases to help diagnose or treat ALK-positive ALCL that occurs in the neurohypophysis and pineal gland.