[Update on marginal zone lymphoma classification, diagnosis and treatment in 2024].

Marginal zone lymphoma (MZL) is the third most frequent lymphoma in Western countries with an increasing incidence with age. There are different histologic subtypes: Splenic MZL (SMZL), Nodal MZL (NZML), Extranodal MZL (EMZL) or MALT lymphoma and more recently, a novel entity called splenic diffuse red pulp small B-cell lymphoma. The accurate diagnosis relies on morphologic, phenotypic, cytogenetic and molecular features in order to rule out other indolent non-Hodgkin lymphomas. First line treatment depends on MZL subtypes: depending on localized or disseminated disease, MALT lymphoma are managed with radiotherapy on immunochemotherapy. SMZL, when requiring therapy, are treated with splenectomy ore more frequently monotherapy Rituximab or immunochemotherapy depending on age, comorbidities and tumor burden. Management of NMZL is often similar to Follicular lymphoma treatment. Treatment of refractory or relapsed MZL takes into account the time between the diagnosis and the progression, the nature and outcomes of previous therapies and the general condition of the patient. Conventional treatments may be a suitable option but novel therapies are more frequently used. In this review, we focus on the role of Bruton Tyrosine Kinases (where only Zanubrutinib has marketing authorization in France), PI3Kinases, Syk and BCL-2 inhibitors as well as on the results of immunomodulatory drugs and more recently the use of bispecific antibodies and T-cell chimeric antigen receptor (CAR-T cell).