Synchronous CNS and systemic involvement in CD30-positive DLBCL: A rare presentation treated with alternating R-CHOP plus HD-MTX and R-HIDAC plus HD-MTX

Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma. Central nervous system (CNS) involvement at diagnosis occurs in approximately 5% of cases. We report an uncommon presentation of a 52-year-old woman diagnosed with CD30-positive DLBCL with synchronous systemic and CNS involvement. She presented with generalized lymphadenopathy and intermittent headaches. Brain magnetic resonance imaging (MRI) revealed a 2.0 × 2.7 × 2.0 cm extra-axial infratentorial mass, while systemic imaging demonstrated widespread nodal disease. Excisional lymph node biopsy confirmed CD30-positive DLBCL. Cerebrospinal fluid analysis was negative for malignant cells. The patient received alternating R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) and R-HIDAC (rituximab plus high-dose cytarabine) with intercalated high-dose methotrexate (HD-MTX), resulting in clinical and neurologic improvement. Post-treatment positron emission tomography–computed tomography (PET-CT) demonstrated a complete metabolic response. End-of-treatment brain MRI confirmed complete radiologic remission. This case underscores the importance of early neuroimaging in DLBCL patients with neurologic symptoms and supports the integration of CNS-directed therapy, particularly in resource-limited settings.