Nodal marginal zone lymphoma: what do we really know?

Typically, when one authors a commentary piece, a good template to follow is to start with some background material, review the major findings of the paper in question, and then focus on areas of controversy and unanswered questions. After reviewing the comprehensive article by Traverse-Glehen et al, we admittedly struggled to follow this template. Why is that? For starters, their review is so thorough, there is not much one can add. Additionally, while there are plenty of unanswered questions, there are few areas of controversy regarding the entity of nodal marginal zone lymphoma. Why so little controversy? Because there is relatively little research specific to this topic, it is hard for controversy to arise. The rarity of this diagnosis is responsible for the lack of large databases or clinical trial data on patients with this type of lymphoma. The authors are to be commended for compiling the several small series that do exist on this topic to create a relatively dense and high-quality overview of the clinical and diagnostic features of this tumor (including morphologic, immunophenotypic, cytogenetic, and molecular features). As the authors mention, there are limited data concerning prognostic markers and standards of care.