Fibrin‐associated diffuse large B‐cell lymphoma

Abstract

A 71-year-old woman presented with lower limb oedema and marked abdominal distension. An abdominal computed tomography scan with contrast medium showed a bulky hypodense mass, 34 cm in maximum diameter, dislocating the right kidney contralaterally (left). The mass had a cystic appearance and a well-defined thickened and focally calcified wall. After its surgical removal, histopathological evaluation revealed an adrenal pseudocyst containing abundant amorphous material. A careful and exhaustive sampling of the mass disclosed, within the fibrinous material, a few clusters of large lymphoid cells (right) with a non-germinal centre B-cell immunophenotype, positive for PAX5, MUM1/IRF4 and CD30. These cells showed an intense and diffuse positive staining with Epstein–Barr virus (EBV)-encoded mRNA by in situ hybridization (EBER-ISH) (see Figure S1). A fibrin-associated EBV-positive large B-cell lymphoma was diagnosed. Fibrin-associated EBV-positive large B-cell lymphoma, a rare lymphoma composed of small aggregates of large cells lying in a background of abundant fibrin, is typically not mass-forming and, therefore, is often detected incidentally. It can arise in unusual sites, such as within a pseudocyst or a cardiac myxoma, or in association with a prosthetic cardiac valve or a metallic implant. It mostly behaves indolently and, particularly when arising in the context of a pseudocyst, it is potentially curable by surgery alone. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.