Plasticity in Classical Hodgkin Composite Lymphomas: A Systematic Review

The co-occurrence of several lymphomas in a patient defines composite/synchronous lymphoma. A common cellular origin has been reported for both contingents of such entities. In the present review, we aimed to gather the available data on composite lymphomas associating a classical Hodgkin lymphoma (cHL) with another lymphoma, to better understand the plasticity of mature B and T-cells. This review highlights that >70% of patients with a composite lymphoma are ≥55 years old, with a male predominance. The most reported associations are cHL with follicular lymphoma or diffuse large B-cell lymphoma, with over 130 cases reported. The cHL contingent is often of mixed cellularity type, with a more frequent focal/weak CD20 expression (30% to 55.6%) compared to de novo cHL, suggesting a particular pathophysiology. Moreover, Hodgkin cells may express specific markers of the associated lymphoma (e.g., BCL2/BCL6 for follicular lymphoma and Cyclin D1 for mantle cell lymphoma), sometimes combined with common BCL2/BCL6 or CCND1 rearrangements, respectively. In addition, both contingents may share similar IgH/IgK rearrangements and identical pathogenic variants, reinforcing the hypothesis of a common clonal origin. Finally, cHL appears to be endowed with a greater plasticity than previously thought, supporting a common clonal origin and a transdifferentiation process during lymphomagenesis of composite lymphomas.

Non-diffuse large B-cell lymphoma transformation from follicular lymphoma: a single-institution study of 19 cases

Diffuse large B-cell lymphoma (DLBCL) is the most common histological transformation (HT) of follicular lymphoma (FL). Other types of HT are very rare, and their incidence, histopathology, and patient outcomes have not been sufficiently described. Here, we assessed the clinicopathological characteristics of 19 cases of non-DLBCL HT of FL in a single institution in Japan to advance the understanding of the disease. Among 889 consecutive patients diagnosed with FL between 2000 and 2018, 191 suffered HT (21%). The median follow-up period was 94 months (range = 3-225). A total of 172 patients (90%) had DLBCL transformation, whereas the remaining 19 patients (10%) exhibited non-DLBCL transformation. In the latter cases, the following diagnoses were made based on morphology, immunohistochemistry, flow cytometry, and fluorescence in situ hybridization analyses: classic Hodgkin lymphoma (7 patients; 4%); high-grade B-cell lymphoma (HGBL) with MYC and BCL2 rearrangements (4 patients; 2%); HGBL, not otherwise specified (4 patients; 2%); B-cell lymphoblastic leukemia/lymphoma (2 patients; 1%); anaplastic large-cell lymphoma-like lymphoma (1 patient; 0.5%); and plasmablastic lymphoma (1 patient; 0.5%). Epstein-Barr virus-encoded RNA-1 did not associate with HT in any of the cases tested (n = 8). Patients with non-DLBCL transformation showed poor outcomes, with a median overall survival of 13 months (range = 2 days-107 months); 10 of the patients (53%) died of HT. In conclusions, non-DLBCL transformation was observed in 10% of patients with HT from FL. Our data show that timely, accurate, and comprehensive histopathological diagnosis is needed to ensure optimal treatment and improve the outcome of these patients.

The broad landscape of follicular lymphoma: Part II

Follicular lymphoma is a neoplasm derived from follicle center B cells, typically both centrocytes and centroblasts, in variable proportions according to the lymphoma grading. The pattern of growth may be entirely follicular, follicular and diffuse and rarely completely diffuse. It represents the second most common non-Hodgkin lymphoma, after diffuse large B-cell lymphoma and it is the most common low-grade mature B-cell lymphoma in Western countries. In the majority of cases, follicular lymphoma is a nodal tumor, occurring in adults and is frequently associated with the translocation t(14;18)(q32;q21)/IGH-BCL2. However, in recent years the spectrum of follicular lymphoma has expanded and small subsets of follicular lymphoma, which differ from common follicular lymphoma, have been identified and included in the current 2017 WHO classification. The aim of our review is to describe the broad spectrum of follicular lymphoma, pointing out that the identification of distinct clinicopathological variants of follicular lymphoma is relevant for the patient outcomes and treatment.

Composite and sequential lymphoma between classical Hodgkin lymphoma and primary mediastinal lymphoma/diffuse large B-cell lymphoma, a clinico-pathological series of 25 cases

Composite and sequential lymphomas involving both classical Hodgkin lymphoma (CHL) and primary mediastinal B-cell lymphoma (PMBCL) are rare phenomena. Beyond the relevant biological interest raised by these cases, treatments and outcome data are poorly covered in the recent literature. This retrospective analysis describes the pathological and clinical characteristics of 10 composite and 15 sequential cases included after a central pathological review. At diagnosis, 70% of the composite lymphomas presented a disseminated and extranodal disease. Among the 15 sequential lymphomas, 12 were CHL at first occurrence and three were PMBCL. Based on their clinical evolution, these sequential lymphomas could be divided into early (i.e., diagnosis of second lymphoma within a year) and late [(i.e., a second lymphoma occurrence occurring after a long period of complete remission]). All composite cases were alive in complete remission after a median follow-up of 34 months. If the early sequential lymphoma presented a particularly poor outcome with a median overall survival shorter than one year, the late cases were efficiently salvaged. Further molecular studies are needed to describe the underlying biology of these rare diseases, possibly representing the extreme of tumour cell plasticity found in grey-zone lymphoma.

Composite t(14;18)-Negative Follicular Lymphoma and Nodular Lymphocyte-Predominant Hodgkin Lymphoma

A composite lymphoma is the rare simultaneous occurrence of two or more distinct lymphomas within a single tissue or organ. Herein, we describe a case of a 51-year-old man presenting with a history of lower limb rash, fatigue, and bulky abdominopelvic lymphadenopathy. An excisional left iliac lymph node biopsy was notable for the composite presence of two distinct lymphoid neoplasms, nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), and follicular lymphoma (FL). Multiplex PCR and FISH analyses failed to demonstrate a t(14;18)(q32;q21) translocation in either composite lymphoma component. A clonal light-chain kappa (V/JC intron-kde) gene rearrangement was detected in the FL component only.

Composite lymphoma with diffuse large B-cell lymphoma and classical Hodgkin lymphoma components: A case report and review of the literature

Composite lymphoma (CL) is an infrequently diagnosed entity in which two or more distinct types of lymphomas occur synchronously in the same organ or anatomical site. Most commonly, CLs are composed of two non-Hodgkin B-cell lymphomas. We present a case of a composite lymphoma with diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS) and classical Hodgkin lymphoma (CHL) components involving the terminal ileum, colon and pericolic lymph nodes. Immunohistochemical evaluation for determination of cell of origin of the DLBCL-NOS component indicated a germinal center B-cell subtype. Immunoglobulin heavy chain fragment length analysis revealed identical dominant monoclonal peaks on the DH1-6-JH reaction, and also a dominant monoclonal peak observed only in the framework II reaction done on the CHL component, indicating a partial clonal relationship between the two components. Additionally, a review of the available literature reveals a total of 20 previously reported cases of CL with DLBCL-NOS and CHL components, and most of the tested cases showed clonal relationship between the two components. The overall findings indicate that in most cases, the two components of CL with DLBCL-NOS and CHL components are clonally related, and suggest a shared origin from a common B-cell precursor.