Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma and often presents with an aggressive clinical course. We report the case of an 84-year-old woman with dementia who presented with a rapidly growing mediastinal mass. Imaging revealed compression of the superior vena cava - an oncological emergency requiring immediate intervention - along with a large pleural effusion, which was confirmed to be a chylothorax, a rare complication of lymphoma. Radiotherapy was started on the day of admission, alongside corticosteroid therapy. A biopsy confirmed peripheral B-cell lymphoma, consistent with stage IE DLBCL. Despite her advanced age, dementia, and other comorbidities, palliative chemotherapy was initiated. This case underscores the challenges of managing aggressive lymphoma in older patients with significant comorbidities and highlights the importance of prompt diagnosis and targeted treatment.