Richter transformation of chronic lymphocytic leukemia into composite diffuse large B-cell and Hodgkin lymphoma

Progression and transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma and B-cell prolymphocytic leukemia: Report from the 2021 SH/EAHP Workshop

OBJECTIVES

Session 3 of the 2021 Workshop of the Society for Hematopathology/European Association for Haematopathology examined progression and transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and B-cell prolymphocytic leukemia (B-PLL).

METHODS

Thirty-one cases were reviewed by the panel. Additional studies such as immunohistochemistry and molecular genetic testing, including whole-exome sequencing and expression profiling, were performed in select cases.

RESULTS

Session 3 included 27 CLL/SLL cases and miscellaneous associated proliferations, 3 cases of B-PLL, and 1 case of small B-cell lymphoma. The criteria for -accelerated CLL/SLL are established for lymph nodes, but extranodal disease can be diagnostically challenging. Richter transformation (RT) is a broad term and includes true transformation from original CLL/SLL clone(s) and clonally unrelated neoplasms. The morphologic, immunophenotypic, and genetic spectrum is diverse with classical and highly unusual examples. T-cell proliferations can also be encountered in CLL/SLL. B-cell prolymphocytic leukemia is a rare, diagnostically challenging disease due to its overlaps with other lymphoid neoplasms.

CONCLUSIONS

The workshop highlighted complexity of progression and transformation in CLL/SLL and B-PLL, as well as diagnostic caveats accompanying heterogeneous presentations of RT and other manifestations of disease progression. Molecular genetic studies are pivotal for diagnosis and determination of clonal relationship, and to predict response to treatment and identify resistance to targeted therapy.

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.

Richter transformation in the oral and maxillofacial area: report of 2 cases and literature review

Richter transformation (RT) is a term used to refer to the development of an aggressive lymphoma, usually of diffuse large B-cell lymphoma type, in a patient with a history of chronic lymphocytic leukemia. It may present with heterogeneous manifestations, including the occurrence of tumors at extranodal sites. To date, only 6 cases of RT involving the oral and maxillofacial region have been reported. Here, we present 2 rare cases of lymphoma initially affecting the maxilla and the lower gingiva, respectively, of female patients with chronic lymphocytic leukemia and review the English language literature about RT manifesting in the oral and maxillofacial tissues.

Chronic Lymphocytic Leukemia with Divergent Richter's Transformation into a Clonally Related Classical Hodgkin's and Plasmablastic Lymphoma: A Case Report

Chronic lymphocytic leukemia (CLL) typically pursues a prolonged course. Its transformation into a more aggressive lymphoma occurs in 2-8% of all patients. Most commonly, diffuse large B-cell lymphoma develops. Transformation into a classical Hodgkin's lymphoma (cHL) occurs in <1%. Plasmablastic transformation has been only rarely reported. Cases of synchronous divergent transformation of CLL into a composite lymphoma are exceedingly rare. We describe the unique occurrence of the transformation of a long-standing CLL into a synchronous clonally related cHL as well as plasmablastic lymphoma (PBL) in an 85-year-old female patient. After 10 years of asymptomatic CLL, our patient was treated with a rituximab-chlorambucil scheme in combination with pegfilgrastim for recurrent infections and the development of B symptoms. Five cycles (of six planned) were administrated with no adverse effects. After the fifth cycle, lymphadenopathy with pronounced B symptoms appeared. Histology showed the presence of cHL in the lymph node, while the bone marrow was infiltrated by PBL. Our patient died in sepsis not receiving further specific oncologic treatment due to her poor general condition. Additional cytogenetic and molecular studies showed that this was a case of mutated CLL with trisomies of chromosomes 12, 3, and 18 (a rare specific +12 plus other-non+19 CLL subgroup). The presence of trisomy 12 has also been proved in plasmablasts and in cHL cells.