Case report: Diffuse large B-cell lymphoma associated with chronic inflammation presenting as a rapidly enlarging perigraft hematoma after TEVAR.

Thoracic endovascular aortic repair (TEVAR) has become the primary treatment for Stanford type B aortic dissection. The differential diagnosis of postoperative periaortic masses typically focuses on hematoma, endoleak, or graft infection. We report the case of a patient who underwent repeat TEVAR for stent-graft fracture 8 years after the index procedure. A periaortic hypodense lesion identified on preoperative computed tomography (CT) was initially interpreted as a hematoma but rapidly progressed into a large soft-tissue mass shortly after the secondary intervention, accompanied by a marked elevation in serum lactate dehydrogenase. Imaging evaluation revealed a discordant pattern: restricted diffusion on magnetic resonance imaging (MRI) with absent enhancement on contrast-enhanced ultrasound (CEUS). Positron emission tomography/computed tomography (PET/CT) demonstrated markedly increased metabolic activity within the lesion. Core needle biopsy confirmed the diagnosis of Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) with a TP53 mutation. Diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI) occurring around a vascular graft and forming a well-defined mass is extremely rare. No previously reported case has simultaneously met the three criteria of a vascular graft background, Epstein-Barr virus-encoded small RNA (EBER) positivity, and the formation of a well-defined mass. Through retrospective analysis of the imaging features in this case, we aim to enhance clinicians' awareness of this rare entity, thereby facilitating earlier diagnosis and reducing misdiagnosis.