RESUMO
Fibrin-associated large B-cell lymphoma is a rare microscopic-sized tumor, typically representing an unexpected finding at sites rich in chronic fibrin deposition. It is associated with Epstein-Barr virus, and has been reported to occur in a wide variety of anatomic sites and clinical scenarios. We report a case arising in a thyroid hyperplastic nodule, only the second case reported in this location. Notably, this is only the fourth case of fibrin-associated large B-cell lymphoma that is not associated with Epstein-Barr virus. We provide a literature review on the clinico-pathological characteristics and outcome of this newly characterized indolent lymphoma type, which has only recently been separated out from the pathologically similar but highly aggressive large B-cell lymphoma associated with chronic inflammation.