[Splenic diffuse red pulp small B-cell lymphoma diagnosed by splenectomy initially mimicking hairy cell leukemia-Japanese variant].

A 62-year-old man presented to the hospital with thrombocytopenia, and splenomegaly was detected. His blood films prepared by natural air drying revealed medium-sized lymphocytes with unevenly distributed large and small villous projections. The cytoplasm was basophilic, nuclei were oval with clumped chromatin, and nucleoli were absent in most cells. Immune phenotypes CD19+, CD20+, CD11c+, FMC7+, IgM+, and Igκ+ were detected. TRAP stain appeared negative, IgH JH chain genes were monoclonally rearranged, and BRAF V600E mutation was not detected. On the basis of these findings, hairy cell leukemia-Japanese variant (HCL-JV) was strongly suspected. The patient was followed up for >4 years without treatment. However, because thrombocytopenia and splenomegaly gradually progressed, splenectomy was performed. Microscopic examination confirmed that the splenic white pulp was atrophic. Moreover, infiltrates comprising small-to-medium-sized atypical lymphocytes with inconspicuous nucleoli were predominantly detected in the congested red pulp. On the basis of these results and immune histochemical findings, the patient was diagnosed with splenic diffuse red pulp small B-cell lymphoma (SDRPL). Here we discussed whether the aforementioned diseases (HCL-JV and SDRPL) are the same; however, further accumulation of cases is essential to draw a definite conclusion.

First reported case of splenic diffuse red pulp small B-cell lymphoma with novel mutations in CXCR4 and TRAF3 genes.

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is a rare B-cell tumor whose genetic characteristics are poorly understood. Here, we introduce the case of a 62-year-old patient with SDRPL who showed progressive elevation of lymphocytes and progressive spleen enlargement. Immunohistochemistry showed that CD20 and CD79a were positive, and the Ki-67 labelling index was approximately 5%, consistent with the pathological features of splenic B-cell lymphoma. Spleen tissue and peripheral blood samples from the patient were sequenced using a next-generation sequencing platform, and mutations possibly were detected in the CXCR4 and TRAF3 genes that may be related to the pathogenesis of the disease. This finding may provide insights into the molecular pathogenesis of SDRPL and assist in molecular diagnosis and targeted therapy for SDRPL.

An Aggressive Course of Transformed Splenic Diffuse Red Pulp Small B-Cell Lymphoma With Novel Somatic Loss-of-Function Mutation in RB1.

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is an extremely rare B-cell lymphoma. The disease is typically indolent and treatment with splenectomy usually results in durable remissions. Here, we present a case of an extremely aggressive course of SDRPL with transformation to diffuse large B-cell lymphoma and multiple relapses immediately following cessation of immunochemotherapy. We provide results from whole-exome sequencing from debut of SDRPL and from following transformed stages and identified a novel somatic mutation in RB1 as the possible driver of this aggressive disease, which has not been reported earlier in SDRPL.

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.

Hairy Cell Leukemia-Japanese Variant: Report of a Patient and Literature Review.

Hairy cell leukemia-Japanese variant (HCL-jv) shares some features with, but differs in other features from, HCL variant. Recently, it has been pointed out that HCL-jv and splenic diffuse red pulp small B-cell lymphoma (SDRPL) possibly constitute the same disease. We report a patient with HCL-jv, in which the neoplastic cells in the resected spleen were positive for CD11c, CD103, tartrate-resistant acid phosphatase (by immunohistochemistry), and weakly positive for cyclin D3. They were negative for CD25, CD123, annexin A1, and BRAF V600E-derived protein. Meta-analysis of HCL-jv cases in the literature showed considerable variation in the expression of HCL-related molecules. Although the clinical features and pattern of splenic involvement of HCL-jv are similar to those of SDRPL, some cytomorphological and phenotypical differences can be pointed out. To confirm whether the weak expression of cyclin D3 in our case suggests a spectrum from HCL-jv to SDRPL or one of the characteristics of HCL-jv, further studies on a large number of cases are necessary.

CD5-Negative, CD10-Negative Low-Grade B-Cell Lymphoproliferative Disorders of the Spleen.

CD5-negative, CD10-negative low-grade B-cell lymphoproliferative disorders (CD5-CD10-LPD) of the spleen comprise a fascinating group of indolent, neoplastic, mature B-cell proliferations that are essential to accurately identify but can be difficult to diagnose. They comprise the majority of B-cell LPDs primary to the spleen, commonly presenting with splenomegaly and co-involvement of peripheral blood and bone marrow, but with little to no involvement of lymph nodes. Splenic marginal zone lymphoma is one of the prototypical, best studied, and most frequently encountered CD5-CD10-LPD of the spleen and typically involves white pulp. In contrast, hairy cell leukemia, another well-studied CD5-CD10-LPD of the spleen, involves red pulp, as do the two less common entities comprising so-called splenic B-cell lymphoma/leukemia unclassifiable: splenic diffuse red pulp small B-cell lymphoma and hairy cell leukemia variant. Although not always encountered in the spleen, lymphoplasmacytic lymphoma, a B-cell lymphoproliferative disorder consisting of a dual population of both clonal B-cells and plasma cells and the frequent presence of the MYD88 L265P mutation, is another CD5-CD10-LPD that can be seen in the spleen. Distinction of these different entities is possible through careful evaluation of morphologic, immunophenotypic, cytogenetic, and molecular features, as well as peripheral blood and bone marrow specimens. A firm understanding of this group of low-grade B-cell lymphoproliferative disorders is necessary for accurate diagnosis leading to optimal patient management.

Splenic Diffuse Red Pulp Small B-Cell Lymphoma with Gastrointestinal Hemorrhage: A Case Report and Literature Review.

BACKGROUND: Splenic diffuse red pulp small B-cell lymphoma (SDRPSBCL) is rare and accounts for less than 1% of non-Hodgkin's lymphoma. As the first or accompanying symptoms of SDRPSBCL, gastrointestinal hemorrhage (GIH) is rather unusual. PATIENTS AND METHODS: We reported on a patient with SDRPSBCL complicated with GIH. According to the enteroscopy, pathological sections of spleen and intestine, immunohistochemistry and other related laboratory examinations, the patient was diagnosed as SDRPSBCL (stage IVb) complicated with colon and rectal ulcers. The clinical manifestations were hematochezia, unformed stool, continuous anal pain and poor quality of life. Subsequently, the patient was treated by six cycles of CHOP (cyclophosphamide + doxorubicin + vincristine + hydroprednisone) regimens. The clinical features, diagnosis and treatment were analyzed retrospectively and the relevant literatures were reviewed. RESULTS: After the first course of chemotherapy, the patient did not have any more bloody stool and the stool was shaped. After six cycles of chemotherapy, the patient's anus was no longer painful and he has been in complete remission according to the result of positron emission tomography CT. CONCLUSION: Through analysis of this case, we could elucidate that after the primary disease was alleviated, the bleeding degree of digestive tract was relieved, which provided the basis for the clinical treatment of this rare disease.

[Chronic B-cell lymphoproliferative disorders with hairy cells]. / Proliférations lymphoïdes B matures à cellules chevelues.

The standardized blood smear examination is the first step in the diagnosis of a B-cell chronic lymphoproliferative disorder and can guide further investigations. In the laboratory, the identification of hairy cells on blood smear is a matter of daily practice. Hairy cell proliferations represent heterogeneous entities and their respective diagnoses can be difficult. If hairy cell leukemia (HCL) and splenic marginal zone lymphoma (SMZL) represent separate entities, the variant form of HCL (HCLv) and splenic diffuse red pulp small B-cell lymphoma (SDRPL) remain provisional entities in the 2008 WHO classification. We discuss the main clinical and biological characteristics of these four entities and appropriate means to characterize, identify and distinguish from each other; standardized blood smear examination, multiparameter flow cytometry analysis, analysis of the repertoire of immunoglobulins heavy chains genes and their mutational status (mutated or unmutated profile), molecular analyses: BRAF gene V600E mutation in HCL and MAP2K1 gene mutations in HCLv. We also discuss the main therapeutic aspects with emphasis on the new targeted drugs that enter into force in the therapeutic arsenal.