Outcome of patients receiving consolidative autologous peripheral blood stem cell transplantation in the frontline treatment of intravascular large B-cell lymphoma: Adult Lymphoma Working Group of the Japan Society for Hematopoietic Cell Transplantation

Intravascular Large B-Cell Lymphoma

CONTEXT.—

Intravascular large B-cell lymphoma (IVLBCL) is a rare hematopathologic entity, posing both a clinical and histologic challenge for diagnosis. Numerous pitfalls can hinder making the diagnosis.

OBJECTIVE.—

To summarize recent developments in literature pertaining to IVLBCL and point out key pitfalls pathologists should be prepared to encounter.

DATA SOURCES.—

Literature review via PubMed search and hospital (Darnall Medical Library) resources.

CONCLUSIONS.—

The 3 primary pitfalls of IVLBCL include masking of IVLBCL, mimicry by IVLBCL, and mimicry of IVLBCL. These scenarios illustrate the importance of histologic pattern recognition and subsequent usage of immunohistochemistry, especially in context of a clinical history that may be noncharacteristic.

Current progress and future perspectives of research on intravascular large B-cell lymphoma

Intravascular large B‐cell lymphoma is a rare disease of the large B cells characterized by selective growth in the lumina of small vessels in systemic organs. Since first reported in 1959, the difficulty of obtaining sufficient tumor cells from biopsy specimens has hampered the elucidation of its underlying biology. Recent progress using xenograft models and plasma cell‐free DNA has uncovered genetic features that are similar to those of activated B‐cell type diffuse large B‐cell lymphoma, including MYD88 and CD79B mutations and frequent alterations in immune check point‐related genes such as PD‐L1 and PD‐L2. Given the improvement in clinical outcomes and a higher risk of secondary central nervous system (CNS) involvement in the rituximab era, a phase 2 trial of R‐CHOP combined with high‐dose methotrexate and intrathecal chemotherapy as a CNS‐oriented therapy has been conducted. This trial, the PRIMEUR‐IVL study, has displayed good progression‐free survival and a low cumulative incidence of secondary CNS involvement. Long‐term follow‐up within this trial is still ongoing. Further understanding of the pathophysiology of the disease and improvements in clinical outcomes are still needed.