Abstract
Primary central nervous system lymphoma (PCNSL) is a rare type of non-Hodgkin's lymphoma that occurs in patients who are elderly and immunocompromised. The most common treatment for PCNSL is high-dose methotrexate-based chemotherapy. Studies have suggested that the radiological response to high-dose methotrexate-based chemotherapy is associated with improved neurocognitive ability that remains stable upon follow-up. However, no study involving patients with an extremely poor neurological status before chemotherapy initiation has been reported, and the neurological prognosis of this group of patients remains unknown. The current case study described 3 patients with PCNSL diagnosed via biopsy who had comatose neurological states due to disease progression prior to treatment. All patients were treated with high-dose methotrexate-based chemotherapy. However, although effective radiological responses to treatment were achieved, no meaningful neurological or cognitive recovery was documented. Patients with PCNSL exhibiting a baseline comatose state have a poor neurological prognosis even with an effective tumour response to chemotherapy. Therefore, rapid detection and prompt treatment are crucial in patients with this disease.