Case Report: Post-transplant lymphoproliferative disorder mimicking Baló's concentric sclerosis.

Post-Transplant Lymphoproliferative Disorder (PTLD) is a lymphoproliferative disease that occurs in recipients of solid organ or hematopoietic stem cell transplants, resulting from the malignant transformation of benign proliferative lymphoid or plasma cell tissue due to immunosuppression. As an immunodeficiency-associated lymphoproliferative disorder, PTLD can affect various organs, including lymph nodes, the gastrointestinal tract, lungs, kidneys, and the central nervous system. The overall prognosis is generally poor. This case report describes a 37-year-old female patient presenting with magnetic resonance imaging (MRI) findings mimicking Baló's concentric sclerosis (BCS). However, pathological biopsy confirmed a diagnosis of monomorphic Primary Central Nervous System PTLD (PCNS-PTLD). The patient was treated with immunosuppression reduction combined with rituximab plus lenalidomide which led to a partial remission. Both PTLD and Baló's concentric sclerosis exhibit significant improvement with high-dose corticosteroid therapy, which can complicate the differential diagnosis. This report aims to summarize the clinical features of a case of PCNS-PTLD that mimicked Baló's concentric sclerosis to enhance the early recognition and diagnosis of PCNS-PTLD.