Definition, diagnosis, and management of intravascular large B-cell lymphoma: Proposals and perspectives from an international consensus meeting

Intravascular large B-cell lymphoma (IVLBCL) is a rare form of diffuse LBCL characterized by preferential intravascular growth of malignant lymphocytes, aggressive behavior, and an often fatal course. IVLBCL usually affects elderly patients with poor performance status, elevated lactic dehydrogenase serum levels, anemia, and B symptoms. It displays some differences in clinical presentation among diverse geographical areas, mostly between patients diagnosed in Western countries and Japan. In addition, data from the literature suggest that pathologic diagnostic criteria as well as clinical features of this disease may be broader than described in current classification scheme(s). Under the sponsorship of the International Extranodal Lymphoma Study Group, clinicians and pathologists with interest in IVLBCL, coming from Western and Eastern countries, joined to reach a consensus on defining features as well as to focus on the most urgent unresolved issues in IVLBCL. To this end, a representative group of IVLBCL patients coming from both the aforementioned geographical areas were collectively analyzed. Additional features of IVLBCL were proposed both under clinical and pathologic stand points. At the meeting, it emerged that IVLBCL may have additional histopathologic/cytologic definition criteria with respect to those currently recommended, some clinical features are not randomly distributed worldwide, recent therapeutic approaches, such as anti-CD20-containing regimens, may improve outcome, and kidney, spleen, and liver involvement may show peculiar histopathologic features. Finally, a provisional practical diagnostic approach to hemophagocytosis-associated patients and a proposal for the most useful criteria in the settings of differential diagnosis are included.