The many faces of nodal and splenic marginal zone lymphomas. A report of the 2022 EA4HP/SH lymphoma workshop

Session 3 of the lymphoma workshop of the XXI joint meeting of the European Association for Haematopathology and the Society for Hematopathology took place in Florence, Italy, on September 22, 2022. The topics of this session were splenic and nodal marginal zone lymphomas, transformation in marginal zone lymphomas, and pediatric nodal marginal zone lymphomas and their differential diagnosis as well as related entities. Forty-two cases in these categories were submitted to the workshop, including splenic lymphomas (marginal zone and diffuse red pulp lymphomas), transformed marginal zone lymphomas (splenic and nodal), nodal marginal zone lymphomas with increased TFH-cells, and pediatric nodal marginal zone lymphomas. The case review highlighted some of the principal problems in the diagnosis of marginal zone lymphomas, including the difficulties in the distinction between splenic marginal zone lymphoma, splenic diffuse red pulp lymphoma, and hairy cell leukemia variant/splenic B-cell lymphoma with prominent nucleoli which requires integration of clinical features, immunophenotype, and morphology in blood, bone marrow, and spleen; cases of marginal zone lymphoma with markedly increased TFH-cells, simulating a T-cell lymphoma, where molecular studies (clonality and mutation detection) can help to establish the final diagnosis; the criteria for transformation of marginal zone lymphomas, which are still unclear and might require the integration of morphological and molecular data; the concept of an overlapping spectrum between pediatric nodal marginal zone lymphoma and pediatric-type follicular lymphoma; and the distinction between pediatric nodal marginal zone lymphoma and "atypical" marginal zone hyperplasia, where molecular studies are mandatory to correctly classify cases.

Incidental Splenic Marginal Zone Lymphoma With Extreme Macrocytosis After Hydroxyurea Use: A Case Report

Splenic marginal zone lymphoma (SMZL) is a low-grade mature B-cell lymphoma that typically presents in the form of splenomegaly and lymphocytosis. The diagnosis is traditionally made through splenic histology, the presence of circulating villous lymphocytes, or bone marrow biopsy. Its treatment can be in the form of chemotherapy, such as rituximab, or active surveillance. This case presentation discusses a 76-year-old female with a long history of hydroxyurea use for an unknown reason presenting with atypical symptoms requiring bone marrow biopsy to diagnose SMZL. This unique case demonstrates the importance of further research and studies into atypical SMZL presentations and hydroxyurea's potential in precipitating secondary malignancies.

Hepatic Infiltration by Splenic Marginal Zone Lymphoma in a Patient With Cured Hepatitis C

Splenic marginal zone lymphoma (SMZL) accounts for only 1-2.7% of all lymphomas. Almost all patients have bone marrow (BM) involvement but only one-third has liver involvement. The higher prevalence of hepatitis C virus (HCV) infection in these patients has led to the hypothesis of viral involvement in lymphomagenesis.

In this report, we present a case of a 48-year-old woman, with cured hepatitis C, presenting with fever, weight loss, nausea, abdominal pain, and jaundice. She had leucocytosis with lymphocytosis, a progressively worsening cytocholestasis, and hepatosplenomegaly. Liver biopsy, immunophenotyping, and BM biopsy were performed, resulting in the diagnosis of SMZL. The patient started chemotherapy (rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine, and prednisolone) with an initial good response, but later progression to high-grade lymphoma and was recommended to undergo salvage chemotherapy followed by auto-transplant.

Despite the unusual liver involvement, we should consider hepatic infiltration by lymphomas, such as SMZL, especially in patients with a history of HCV infection.

Recurrent autoimmune hemolytic anemia in splenic marginal zone lymphoma

Autoimmune hemolytic anemia (AIHA) is a condition associated with an extensive differential diagnosis that includes lymphoid malignancies. Although AIHA occurs in about 10–25% of patients with chronic lymphocytic leukemia, it is also reported to occur in all of the other lymphoid subtypes. In this article, we report a case of recurrent AIHA in a 67-year-old woman with two acute episodes of hemolysis separated by 3 years of hematologic remission. Both episodes were severe enough to require blood transfusion, oral steroids, and rituximab. Bone marrow biopsy and immunophenotyping using flow cytometry done during both admissions confirmed the presence of splenic marginal zone lymphoma.

Important Diagnostic Clues for Diagnosing Splenic Marginal Zone Lymphoma in Absence of Splenic Histology

Splenic Marginal Zone Lymphoma (SMZL) is a rare B-cell neoplasm comprising less than 2% of non-Hodgkin lymphomas. We hereby report a case of SMZL in a 66-year-old female who presented with fever and massive splenomegaly. Peripheral blood smear examination showed atypical lymphoid cells showing variable cytoplasmic processes. Flowcytometric immunophenotyping of peripheral blood showed tumour cells which were found to be positive for CD19, CD79b and showing kappa light chain restriction along with lack of expression for CD5, CD10, CD23, CD103 and lambda. These findings were suggestive of B cell chronic lymphoproliferative disorder. Various differential diagnoses considered in this case were analysed by using different diagnostic clues to arrive at the diagnosis. Bone marrow examination and Immunohistochemical (IHC) analysis showed tumour cells in nodular, interstitial and intrasinusoidal pattern of infiltration which were positive for CD20 and CD79b with kappa light chain restriction and lack of expression of CD5, CD10, CD23 and CD103 which further corroborated the flowcytometric immunophenotyping. The diagnosis of SMZL is arrived at by a combination of diagnostic clues like clinical features, peripheral smear findings, flowcytometric immunophenotyping, morphological and IHC findings in bone marrow biopsy. This case highlights the significance of flowcytometric immunophenotyping and bone marrow biopsy with immunohistochemistry to arrive at a diagnosis of SMZL even in absence of splenic histopathology.

Splenic marginal zone lymphoma: a literature review of diagnostic and therapeutic challenges

Splenic marginal zone lymphoma (SMZL) is a low-grade B-cell non-Hodgkin's lymphoma characterized by massive splenomegaly, moderate lymphocytosis with or without villous lymphocytes, rare involvement of peripheral lymph nodes and indolent clinical course. As a rare disease, with no randomized prospective trials, there is no standard of care for SMZL so far. Splenectomy has been done for many years as an attempt to control disease, but nowadays it has not been encouraged as first line because of new advances in therapy as rituximab, that are as effective with minimal toxicity. Facing these controversies, this review highlights advances in the literature regarding diagnosis, prognostic factors, treatment indications and therapeutic options.

B-cell Non-Hodgkin Lymphomas with Plasmacytic Differentiation

B-cell non-Hodgkin lymphomas with plasmacytic differentiation are a diverse group of entities with extremely variable morphologic features. Diagnostic challenges can arise in differentiating lymphoplasmacytic lymphoma from marginal zone lymphoma and other low-grade B-cell lymphomas. In addition, plasmablastic lymphomas can be difficult to distinguish from diffuse large B-cell lymphoma or other high-grade lymphomas. Judicious use of immunohistochemical studies and molecular testing can assist in appropriate classification.