Hyper‐intense lesion in the pons on brain magnetic resonance imaging in a patient with diffuse large B‐cell lymphoma

Abstract

A 63-year-old man was initially diagnosed with stage IE (paranasal cavity) diffuse large B-cell lymphoma (DLBCL). He received three cycles of R-CHOP therapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) and involved field radiotherapy, followed by intrathecal methotrexate for the prophylaxis of central nervous system (CNS) involvement. After treatment, he achieved complete metabolic response (CMR) and maintained it for 8 years. At 72 years old, he presented with persistent fever and splenomegaly. Bone marrow biopsy (BMB) demonstrated the infiltration of DLBCL cells. He received six cycles of R-CHOP therapy and achieved second CMR. However, 1 year later, he presented with thrombocytopenia, a high LDH level, and splenomegaly. Although no infiltration of lymphoma cellswas noted onBMB, random skin biopsy revealed the infiltration of DLBCL cells in the luminaof small-sized vessels of subcutaneous fat tissue. A hyper-intense lesion in the pons (arrow) on brainmagnetic resonance imaging (MRI) was observed on T2-weighted imaging (T2WI) (A) and diffusion-weighted imaging (dWI) (B) (Figure 1). However, he had no neurological symptoms, and cerebrospinal fluid testing confirmed no infiltration of lymphoma cells. He received R-GDP therapy (rituximab, gemcitabine, dexamethasone, and cisplatin). Thrombocytopenia, high LDH, and splenomegaly improved after the first cycle. Moreover, MRI demonstrated disappearance of the hyper-intense lesion in the