[Diffuse large B-cell lymphoma with central pontine myelinolysis without rapid changes in serum sodium levels]

Central pontine myelinolysis (CPM) typically arises from the rapid correction of hyponatremia. A literature search showed that CPM secondary to malignant lymphoma is rare, with only 11 reported cases. An 80-year-old woman presented with anorexia as her primary symptom and was subsequently diagnosed with diffuse large B-cell lymphoma (DLBCL) following an axillary lymph node biopsy. Shortly after treatment initiation, she experienced convulsions and altered consciousness. Brain MRI revealed a symmetrical lesion in the pons, but gadolinium enhancement was not observed and cerebrospinal fluid cytology showed negative results. Despite the absence of a history of hyponatremia, we diagnosed CPM secondary to malignant lymphoma due to the consistent MRI findings and previous similar case reports. Chemotherapy for DLBCL was continued, leading to gradual improvement of the pontine lesion and the patient's neurological status. Given the rarity of CPM secondary to malignant lymphoma, we present a summary of previously reported cases.