Recurrent fibrin associated diffuse large B-cell lymphoma: A case report

Fibrin- associated diffuse large B cell lymphoma (FA-DLBCL) is a rare entity, often incidental finding, categorized under “diffuse large B cell lymphoma associated with chronic inflammation (DLBCL-CI)“ in 2017 World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues. Here we report a 48-year-old male with FA-DLBCL who experienced recurrence within one year from initial presentation. The patient had a history of an abdominal aortic aneurism and underwent an endovascular aneurysm repair (EVAR) in 2013. Later in 2019, he was found by CT aortogram to have endoleak of the aneurysm repair. He underwent an open abdominal aortic aneurysm repair with explant of the endovascular stent. The explanted graft was sent to pathology and was found on gross examination to have ample adherent tissue. On microscopic examination this tissue was composed of abundant fibrinous material with several foci of large pleomorphic lymphocytes with enlarged round to polyhedral nuclei, prominent nucleoli, open chromatin, and scanty cytoplasm. Necrosis was also seen in a largest focus of tumor infiltrate. By immunohistochemistry, the atypical, large lymphocytes expressed CD20 and MUM-1; and positive for EBV, by Epstein-Barr virus (EBV) in situ hybridization (EBER-ISH). Together, the diagnosis for FA-DLBCL was made. Further work up by PET scan showed no active disease. The patient re-presented 10 months later with right lower extremity ischemia due to the vascular graft thrombosis. The thrombectomy specimen showed identical findings of his initial FA- DLBCL. Here we discuss the clinicopathologic findings of this entity and the importance of clinical follow up.