Primary Bone Lymphoma Exhibits a Favorable Prognosis and Distinct Gene Expression Signatures Resembling Diffuse Large B-Cell Lymphoma Derived From Centrocytes in the Germinal Center

Conditional survival of patients with primary bone lymphoma of the spine: how survival changes after initial diagnosis

Background

The current survival prediction methodologies for primary bone lymphoma (PBL) of the spine are deficient. This study represents the inaugural utilization of conditional survival (CS) to assess the outcome of this disease. Moreover, our objective was to devise a CS-based nomogram for predicting overall survival (OS) in real-time for spinal PBL.

Methods

Patients with PBL of the spine diagnosed between January 2000 and December 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The OS was determined through the Kaplan-Meier method. The CS characteristic of patients with spinal PBL was delineated, with the CS being estimated utilizing the formula: CS(α|β) = OS(α+β)/OS(β). CS(α|β) denotes the probability of additional α-year survivorship, assuming the patient has already survived β years after the time of observation. Three methods including univariate Cox regression, best subset regression (BSR) and the least absolute shrinkage and selection operator (LASSO) regression were used to identify predictors for CS-based nomogram construction.

Results

Kaplan-Meier analysis was executed to determine the OS rate for these patients, revealing a survival rate of 68% and subsequently 63% at the 3-year and 5-year mark respectively. We then investigated the CS patterning exhibited by these patients and discovered the survival of PBL in the spine progressively improved with time. Meanwhile, through three different prognostic factor selection methods, we identified the best predicter subset including age, tumor histology, tumor stage, chemotherapy and marital status, for survival prediction model construction. Finally, we successfully established and validated a novel CS-based nomogram model for real-time and dynamic survival estimation. Moreover, we further designed a risk stratification system to facilitate the identification of high-risk patients.

Conclusions

This is the first study to analyze the CS pattern of PBL of the spine. And we have also developed a CS-based nomogram that provide dynamic prognostic data in real-time, thereby aiding in the formulation of personalized treatment strategies in clinical practice.

Follicular Lymphoma Presenting With Symptomatic Bone Involvement: A Clinicopathologic and Molecular Analysis of 16 Cases

Primary bone lymphoma (PBL) is rare and mostly represented by diffuse large B-cell lymphomas (DLBCL). Follicular lymphoma (FL), albeit commonly disseminating to the bone marrow, rarely presents primarily as bone lesions. Here, we studied 16 patients (12 men:4 women, median age 60 years) who presented with bone pain and/or skeletal radiologic abnormalities revealing bone FL. Lesions were multifocal in 11 patients (spine ± appendicular skeleton), and unifocal in 5 patients (femoral, tibial, or vertebral). An infiltrate of centrocytes and centroblasts (CD20+ CD5- CD10+ BCL2+ BCL6+) with abundant reactive T cells and an increased reticulin fibrosis massively replaced the marrow spaces between preserved bone trabeculae. The pattern was diffuse ± nodular, often with paratrabecular reinforcement and/or peripheral paratrabecular extension. Ki-67 was usually <15%. Two cases had necrosis. BCL2 rearrangement was demonstrated in 14 of 14 evaluable cases (with concomitant BCL6 rearrangement in one). High-throughput sequencing revealed BCL2, KMT2D, and TNFRSF14 to be the most frequently mutated genes. After staging, 5 qualified for PBL (3 limited stage) and 11 had stage IV systemic FL. All patients received rituximab ± polychemotherapy as firstline treatment, and 7 received local therapy (6 radiotherapy and 2 surgery). Three patients experienced transformation to DLBCL. At the last follow-up (15/16, median 48 months), 11 patients achieved complete remission, including all cases with PBL and most patients with limited extraosseous disease (3-year progression-free survival 71%). One patient died of unrelated cause (3-year overall survival 91%). FL may manifest as a localized or polyostotic bone disease. A minority represent PBL, whereas most reveal systemic disease.

Primary bone diffuse large B-cell lymphoma (PB-DLBCL): a distinct extranodal lymphoma of germinal centre origin, with a common EZB-like mutational profile and good prognosis

AIMS

Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is not recognized as a separate entity by the current classification systems. Here we define and highlight its distinctive clinical presentation, morphology, phenotype, gene expression profile (GEP), and molecular genetics.

METHODS

We collected 27 respective cases and investigated their phenotype, performed gDNA panel sequencing covering 172 genes, and carried out fluorescence in situ hybridization to evaluate MYC, BCL2, and BCL6 translocations. We attempted to genetically subclassify cases using the Two-step classifier and performed GEP for cell-of-origin subtyping and in silico comparison to uncover up- and downregulated genes as opposed to other DLBCL.

RESULTS

Most cases (n = 22) were germinal centre B-cell-like (GCB) by immunohistochemistry and all by GEP. Additionally, PB-DLBCL had a mutational profile similar to follicular lymphoma and nodal GCB-DLBCL, with the exception of more frequent TP53 and B2M mutations. The GEP of PB-DLBCL was unique, and the frequency of BCL2 rearrangements was lower compared to nodal GCB-DLBCL. The Two-step classifier categorized eight of the cases as EZB, three as ST2, and one as MCD.

CONCLUSION

This study comprehensively characterizes PB-DLBCL as a separate entity with distinct clinical and morpho-molecular features. These insights may aid in developing tailored therapeutic strategies and shed light on its pathogenesis.

Primary Bone Lymphoma Masquerading as Multiple Myeloma: Challenges in the Diagnostic Workup of Severe Hypercalcemia

In this case, we explore the diagnostic workup of a patient presenting with symptomatic hypercalcemia. Initially suspected to have multiple myeloma, the diagnostic evaluation instead unveiled non-germinal center (non-GC) diffuse large B-cell lymphoma (DLBCL). DLBCL is the most common histologic subtype of non-Hodgkin lymphoma and is heterogeneous in terms of presentation, genetic drivers, and morphology. As primary bone DLBCL is exceedingly rare, the case presented proved to be a diagnostic challenge. The patient presented with one week of weakness, one to two days of nausea, and leg pain. On admission, hypercalcemia, renal failure, anemia, and lytic bone lesions were present and suggestive of multiple myeloma. However, serum protein electrophoresis and immunoglobulin levels did not fit the 2016 World Health Organization (WHO) diagnostic criteria for multiple myeloma. A negative bone marrow biopsy also argued against a diffuse plasma cell neoplasm. Finally, a biopsy from another bone lesion was diagnostic of DLBCL. This case discusses an unusual presentation of DLBCL.

Emerging entities: high-grade/large B-cell lymphoma with 11q aberration, large B-cell lymphoma with IRF4 rearrangement, and new molecular subgroups in large B-cell lymphomas. A report of the 2022 EA4HP/SH lymphoma workshop

Emerging entities and molecular subgroups in large B-cell lymphomas (LBCLs) were discussed during the 2022 European Association for Haematopathology/Society for Hematopathology workshop in Florence, Italy. This session focused on newly recognized diseases and their diagnostic challenges. High-grade/large B-cell lymphoma with 11q aberration (HG/LBCL-11q) is defined by chromosome 11q-gains and telomeric loss. FISH analysis is recommended for the diagnosis. HG/LBCL-11q can occur in the setting of immunodeficiency, including ataxia-telangiectasia, and predominates in children. The morphological spectrum of these cases is broader than previously thought with often Burkitt-like morphology and coarse apoptotic bodies. It has a Burkitt-like immunophenotype (CD10+, BCL6+, BCL2-) but MYC expression is weak or negative, lacks MYC rearrangement, and is in contrast to Burkitt lymphoma 50% of the cases express LMO2. LBCL with IRF4 rearrangement (LBCL-IRF4) occurs mainly in the pediatric population but also in adults. LBCL-IRF4 has an excellent prognosis, with distinguishing molecular findings. IRF4 rearrangements, although characteristic of this entity, are not specific and can be found in association with other chromosomal translocations in other large B-cell lymphomas. Other molecular subgroups discussed included primary bone diffuse large B-cell lymphoma (PB-DLBCL), which has distinctive clinical presentation and molecular findings, and B-acute lymphoblastic leukemia (B-ALL) with IGH::MYC translocation recently segregated from Burkitt lymphoma with TdT expression. This latter disorder has molecular features of precursor B-cells, often tetrasomy 1q and recurrent NRAS and KRAS mutations. In this report, novel findings, recommendations for diagnosis, open questions, and diagnostic challenges raised by the cases submitted to the workshop will be discussed.

Comparison of the Effect of Chemoradiotherapy and Chemotherapy on the Survival of Patients with Primary Diffuse Large B-Cell Lymphoma of the Spine: A SEER-Based Study

OBJECTIVE

The role of radiotherapy in primary spinal diffuse large B-cell lymphoma (PB-DLBCL) remains controversial. This study explored the effects of chemoradiotherapy and chemotherapy alone on the survival of patients with PB-DLBCL and established an instructive nomogram.

METHODS

Survival analysis using the Kaplan-Meier method and log-rank test was performed for patients diagnosed with PB-DLBCL from 1983 to 2016, identified in the Surveillance Epidemiology and End Results database. The Cox regression model was used to analyze the effects of each variable on the overall survival (OS) and construct a nomogram for predicting OS in patients.

RESULTS

Overall, 873 patients with PB-DLBCL were included. The patients were divided into the 1983-2001 (227 [26%]) and 2002-2016 (646 [74%]) groups. The 5-and 10-year OS rates of patients with PB-DLBCL in the 2002-2016 group were 62.8% and 49.9%, respectively. The results of the multivariate Cox regression analysis in the 2002-2016 group showed that age, stage, marriage, and treatment strategy were independent prognostic factors. Kaplan-Meier analysis showed that the OS of patients who underwent chemoradiotherapy from 2002 to 2016 was significantly better than that of patients treated with chemotherapy alone. Further subgroup analysis of patients with different stages of DLBCL and at different ages showed that chemoradiotherapy had a better prognosis than chemotherapy alone in stages I-II and age >60 years, whereas the advantages of chemoradiotherapy were not reflected in stages III-IV and age <60 years.

CONCLUSIONS

Chemoradiotherapy improves the OS of patients with PB-DLBCL who are aged >60 years or have stage I-II disease. The nomograms established in this study can help clinicians determine prognosis and select treatment strategies.

Primary Diffuse Large B-Cell Lymphoma of the Bone

Primary lymphoma of the bone (PLB) is a rare lymphoproliferative neoplasm that can present either as solitary or multiple bone lesions. We report four patients with PLB who were successfully treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) followed by consolidative radiotherapy. All patients achieved a complete remission and had excellent long-term outcomes. PLB has a favorable response to combined modality treatment with chemoimmunotherapy and radiation. Long-term outcomes of PLB tend to be better than those of non-osseous diffuse large B-cell lymphoma.

Pathological fracture due to primary bone lymphoma in a patient with a history of prostate cancer: A case report and review of literature

Primary bone lymphoma (PBL) is a rare extranodal presentation within lymphomas and primary bone malignancies. Pathologic fracture (PF) is a common complication of metastatic bone disease but is, rarely, the presentation of a primary bone tumor. We report a case of an 83-year-old man with a history of untreated prostate cancer, presenting with atraumatic fracture of his left femur after months of intermittent pains and weight loss. Radiographic workup revealed a lytic lesion suspicious for PF secondary to metastatic prostate cancer; however, initial core biopsy results were inconclusive for malignancy. A complete blood count with differential and complete metabolic panel was within normal limits. During surgical fixation and nailing of the femur, a reaming biopsy was performed as a repeat measure and revealed diffuse large B-cell lymphoma. Staging with positron emission tomography and computed tomography found no evidence of lymphatic or visceral involvement and chemotherapy was promptly initiated. This case highlights the diagnostic workup challenges for PF secondary to PBL, especially in the setting of concurrent malignancy. Because of the non-specific presentation of a lytic lesion on imaging associated with atraumatic fracture, we highlight PBL as an important diagnostic consideration.

Primary Bone Lymphoma: A Review of the Literature with Emphasis on Histopathology and Histogenesis

Primary bone lymphoma (PBL) is a rare neoplasm of malignant lymphoid cells presenting with one or more bone lesions without nodal or other extranodal involvement. It accounts for approximately 1% of all lymphomas and 7% of malignant primary bone tumors. Diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS) represents the predominant histological type and constitutes over 80% of all cases. PBL may occur at all ages with a typical diagnosis age of 45–60 years and a slight male predominance. Local bone pain, soft tissue edema, palpable mass and pathological fracture are the most common clinical features. Diagnosis of the disease, which is frequently delayed due to its non-specific clinical presentation, is based on the combination of clinical examination and imaging studies and confirmed by combined histopathological and immunohistochemical examination. PBL can develop in any part of the skeleton, although it occurs most commonly in the femur, humerus, tibia, spine and pelvis. The imaging appearance of PBL is highly variable and unspecific. In terms of the cell-of-origin, most cases of primary bone DLBCL (PB-DLBCL), NOS belong to the germinal center B-cell-like subtype and specifically originate from germinal center centrocytes. PB-DLBCL, NOS has been considered a distinct clinical entity based on its particular prognosis, histogenesis, gene expression and mutational profile and miRNA signature. PBL carries a favorable prognosis, especially when treated with combined chemoradiotherapy.

Targetable alterations in primary extranodal diffuse large B-cell lymphoma

Primary extranodal diffuse large B-cell lymphoma (PE-DLBCL) is a heterogeneous subgroup of DLBCL. We investigated the prevalence and prognostic value of surface expression of PD-L1, PD1, and CD30, copy number of 9p24.1 (PD-L1 region), and mutations in MYD88, CD79B, CARD11, and BTK in a cohort of 116 patients, localized in the mediastinum (PMBL, n = 12), ear, nose and throat (ENT, n = 28), central nervous system (n = 29), testis (n = 7), breast (n = 4), stomach (n = 10), bone (n = 8), spleen (n = 2), and skin (n = 16). PD-L1 expression is most frequent in PMBL (92%), followed by lymphomas originating in the stomach (57%), ENT (23%), and skin (18%). PD1 was expressed at low levels in less than 13% of PE-DLBCL, while CD30 expression was found in 58% of PMBL. Mutation analysis revealed an unexpectedly high frequency of MYD88 and CD79B mutations in ENT lymphomas (46% and 50%, respectively). CARD11 mutations are rare but more frequently found in gastric lymphomas (30%), suggesting BTK resistance. Thirty-four of 113 (30%) of the lymphomas harbored both MYD88 and CD79B mutations. Lower overall and progression-free survival rates were found for cases with MYD88, CD79B, and BTK mutations. These data confirm the biologic singularity of PE-DLBCLs and provide some suggestions for targeted therapies.

Proposal of Diagnostic Approach of Periodontal Primary Non Hodgkin Lymphoma of Bone with Flow Cytometry as an Essential Diagnostic Component

BACKGROUND

Primary bone lymphoma is a rare type of lymphoid neoplasm with favorable prognosis, where Primary Non Hodgkin Lymphoma of bone (PB-NHL) is most common with the subtype. Amongst PB-NHL, diffuse large Bcell lymphoma represents the majority of cases. The mandible is a very uncommon site of involvement, presenting as a painful bone mass with high suspicion of osteomyelitis.

METHODS

We report the case of a 45-year-old male with no significant past medical history who was admitted to the hospital with a large right jaw mass and pain after recent tooth removal. The original tissue biopsy was not diagnostic, and cultures were found to be negative for microorganisms. Due to enlargement of the mass, a fine needle aspiration (FNA) was done. At the time of rapid onsite evaluation of the FNA, atypical lymphoid cells were seen, and material was obtained for flow cytometry (FC) evaluation. This revealed an aberrant clonal B-cell population. The consequent immunohistochemical evaluation of original material supported the diagnosis of PB-NHL. After chemotherapy patient improved.

RESULTS

After an extensive English language literature review, we identified and summarized the clinical presentations, diagnostic procedures, histopathologic features, treatment methods, and outcomes of forty-two cases of periodontal PB-NHL. Based on our findings, we propose a set of clinical features at initial presentation to increase the clinical suspicion of periodontal PB-NHL for practitioners.

CONCLUSION

Based on our institution's experience and the literature review conclusions, we propose the University of Texas Medical Branch diagnostic approach for PB-NHL and suggest that FNA and FC should be utilized as the essential diagnostic component. The fast and efficient diagnosis of PB-NHL can facilitate the correct treatment and sufficiently improve patient care.

Limited-stage Diffuse Large B-cell Lymphoma

DLBCL, the most common lymphoma subtype, is localized in 25-30% of patients. Prognosis in patients with limited-stage DLBCL (LS-DLBCL) is excellent with 10-year overall survival of at least 70-80%. Improved insights into the disease biology, the availability of positron-emission tomography (PET) scans and recent dedicated clinical trials within this unique population, have led to evolving treatment paradigms. However, no standard definition of LS-DLBCL exists, and while generally defined as Ann Arbor stages I-II disease with largest mass size <10cm in diameter, variations across studies cause challenges in interpretation. Similar to advanced-stage disease, R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) immunochemotherapy forms the basis of treatment, with combined modality therapy including 3 cycles of systemic treatment and involved-site radiation therapy being a predominant historical standard. Yet the well-described continuous risk of relapse beyond 5 years and established late complications of radiotherapy have challenged previous strategies. More rigorous baseline staging and response assessment with PET may improve decision making. Recent clinical studies have focused on minimizing toxicities while maximizing disease outcomes using strategies such as abbreviated immunochemotherapy alone and PET-adapted radiotherapy delivery. This comprehensive review provides an update of recent literature with recommendations for integration into clinical practice for LS-DLBCL patients.

Unexpected Primary Extranodal Marginal Zone Lymphoma of Bone in Amputation and Arthroplasty Specimens

OBJECTIVES

Amputation due to gangrene and arthroplasty for degenerative joint disease are common orthopedic procedures and are expected to increase as populations age. Histopathologic examination of these specimens can identify unsuspected diseases.

METHODS

We reviewed gangrenous amputations and large joint arthroplasty specimens for diagnosis of unexpected lymphoma, January 2014 to January 2020. Pathology and medical records were reviewed to determine diagnosis, treatment, and outcome.

RESULTS

Five cases (0.08%) of unexpected primary extranodal marginal zone lymphoma (MZL) centered in bone were identified in 1,624 amputations for gangrene and 4,163 arthroplasty specimens. The female-to-male distribution was 3:2. Median age was 71 years (range, 62-87). The 3 cases arising in the setting of gangrene involved the first toe phalanges and metatarsals, and the femoral head was involved in all cases of joint disease (2 cases). The bone showed variable (10%-80%) infiltration by dense populations of small lymphoid cells with MZL immunophenotype. One patient died from sepsis 18.5 months after diagnosis; all others are alive with a median follow-up of 27.45 months.

CONCLUSIONS

Histopathologic examination of nonneoplastic orthopedic specimens identifies unexpected primary bone extranodal MZL in a small percentage of cases. This neoplasm may be the result of chronic antigenic stimulation in some circumstances.

Limited-stage diffuse large B-cell lymphoma: current management and challenges

Twenty-five to thirty per cent of diffuse large B-cell lymphoma (DLBCL) presents as limited stage (I-II). Prognosis is generally excellent with four to six cycles of R-CHOP alone (rituximab, cyclophosphamide, vincristine, doxorubicin, prednisolone) or combined-modality therapy with three or four cycles and involved-site radiotherapy (RT). There is growing interest in optimising algorithms to retain disease control whilst minimising long-term toxicity, with several recent studies focusing on the safety of abbreviating chemotherapy and omitting RT in low-risk patients and the utility of PET-based response-adapted approaches. As these studies are limited to younger patients without risk factors, application of similar approaches in elderly or higher-risk patients is hampered by a lack of evidence. Whilst there has been a move away from using RT in low-risk patients, it remains a useful adjunct in specific situations. Current evidence cannot exclude a clinically meaningful benefit from RT even in low-risk patients and, given the low expected toxicity from modern RT techniques, a risk-benefit assessment should be individualised and considered in a multidisciplinary fashion. The optimal approach for extranodal limited-stage DLBCL (~40% of cases) varies according to site of origin. Herein we discuss the latest clinical trial evidence and how this can be applied in routine practice.

Role of Radiation Therapy Differs Between Stages in Primary Bone Large B-Cell Lymphoma in Rituximab Era: A Population-Based Analysis

Background: Primary bone B-cell lymphoma (PB-DLBCL) is a rare entity for which existing data is limited. Whether radiotherapy (RT) should be omitted in the modern treatment of PB-DLBCL is still under debate. We used the SEER database to compare the outcomes among adult patients treated with and without RT in rituximab era. Methods: We included adult patients with PB-DLBCL diagnosed from 2002 to 2016 from SEER 18. The effect of RT on overall survival (OS) using univariate (UVA) and multivariate (MVA) Cox proportional regression and propensity score matching (PSM) was assessed for the entire cohort and subgroups by stages. We calculated the standardized incidence ratio to estimate the short- and long-term risk for second primary malignancies (SPM) from 2002 to 2016 in SEER 18 and 1983-2016 in SEER 9. Results: A total of 1,320 patients were identified, including 856 with early-stage (ES) and 464 with advanced-stage (AS). A decreasing trend was observed in the ES cohort after 2002, while the rate of RT utilization remained stable in the AS cohort over the past three decades. Most patients in ES (63.9%) underwent RT, whereas only 42.2% of AS patients received it. RT significantly improved survival both in UVA and MVA (P < 0.001, P = 0.010, respectively). PSM analysis further validated the survival advantage of RT (P = 0.018). Moreover, a novel web-based prediction model was established to individualize the potential benefit from RT. In subgroup analyses, OS was improved with RT in those who had ES disease (p < 0.001) but not in those who had AS disease (P = 0.776). With short-term follow up in SEER 18, none of the subgroups showed a significantly elevated risk of developing SPMs. However, RT significantly elevated the late toxicities of second malignancies in ES patients diagnosed at the age of 18-39 or those with appendicular sites of bone involvement. Conclusion: This population-based analysis is the largest PB-DLBCL dataset to date and demonstrates a significant survival benefit associated with RT in early stages rather than advanced stages. In the absence of randomized controlled trials, RT should be considered in ES disease with cautions of second cancers in specific subsets of patients.

Aggressive B-cell lymphomas with a primary bone marrow presentation

Aggressive B-cell lymphomas present as a heterogeneous spectrum of disease. A primary diagnosis in the bone marrow (BM) may be challenging in terms of diagnostic classification and clinical handling, owing to limited architectural information. Aggressive B-cell lymphomas can be subdivided into entities that typically present primarily in the BM, and cases with BM involvement in which the bulk of disease is present in other organs. One main topic at the 2018 BM workshop of the European Association of Haematopathology/Society of Hematopathology was therefore aggressive B-cell lymphomas with a primary BM presentation. The spectrum of cases submitted to this topic gave a good overview of commonly encountered problems, as well as unusual manifestations, and highlighted areas of imprecise disease definitions and diagnostic grey zones. The categories submitted to the workshop included cases of Burkitt lymphoma (BL) with unusual features, high-grade B-cell lymphomas (HG-BCLs) with and without so-called double/triple-hit, and diffuse large B-cell lymphomas (DLBCLs) with a primary BM presentation. Areas of difficulties included the morphological boundaries of HG-BCL not otherwise specified, cases with MYC and bcl-2 or bcl-6 translocations and terminal deoxynucleotidyl transferase (TdT) expression, which were categorised as B-cell lymphoblastic leukaemia/lymphoma if most cells showed TdT positivity, and the clinicopathological overlap between intravascular large B-cell lymphoma, CD5-positive DLBCL, and DLBCL with primary presentations in the BM, spleen, and liver. This review summarises our understanding of the main aggressive B-cell lymphoma categories with a common primary BM presentation and potential problem areas, and makes suggestions for the immunophenotypic and genetic work-up, illustrated by the interesting and challenging cases submitted to the workshop.

Large B-cell lymphoma presenting primarily in bone marrow is frequently associated with haemophagocytic lymphohistiocytosis and has distinct cytogenetic features

The criteria for primary bone marrow large B-cell lymphoma (PBMLBCL) have not yet been clearly established. We aimed to investigate the clinicopathological features of PBMLBCLs (27 cases) and large B-cell lymphomas (LBCLs) with secondary marrow involvement (55 cases). PBMLBCL was defined as LBCLs presenting initially in bone marrow without lymphadenopathy, extramedullary tumour or localised bone tumour, and no evidence of transformation from low grade B-cell lymphoma. Compared with the patients in the secondary group, more patients in the primary group had haemophagocytic lymphohistiocytosis, cytogenetic aberrations, cytopenias, and atypical lymphocytes in peripheral blood. The most common chromosome abnormality in both groups was 6q deletion. The primary group had additional chromosome 10, 2, and 3 abnormalities. The acquired chromosome 10 aberration was associated with the risk of haemophagocytic lymphohistiocytosis. The 1-year survival rate was lower in the primary group than in the secondary group; however, the difference was not significant when the cases without chemotherapy plus rituximab were excluded. Moreover, multivariate analysis revealed that relatively high white blood cell count, not receiving chemotherapy plus rituximab, and cytogenetic aberrations were poor prognostic factors in the secondary group, but only not receiving chemotherapy plus rituximab was retained in the primary group. In conclusion, PBMLBCL is genetically and clinically distinct. Although patients with PBMLBCL generally have a poor outcome, the disease is treatable and some patients become long-term survivors.

Multiple osteolytic lesions due to Double-Expressor Primary non-Hodgkin Lymphoma of the Bone

Primary non-Hodgkin lymphoma of the bone (PLB) is a rare type of non-Hodgkin’s lymphoma (NHL) that affects the skeletal system with or without regional lymph node involvement. We present the case of a 74-year-old female patient with pain due to multifocal osteolytic lesions. The diagnosis of diffuse large B-cells (non-GCB) phenotype was made by clinical, laboratory, histopathological examination accompanied by an extensive immunohistochemical profile of one of the skeletal lesions.

Primary Bone Lymphoma in Axial Skeleton in a Middle-Aged Female Presented as Recurrent Anemia

Primary bone lymphoma (PBL) is a peculiar extranodal presentation of non-Hodgkin's lymphoma. Primary bone diffuse large B-cell lymphoma (DLBCL) is the most common pathological type, comprising about 80% of PBL. The diagnosis of PBL depends on the combined clinical examination and imaging studies and is confirmed with immunohistochemical examination. Due to the rarity of this disease, more relative studies and case reports are needed to provide insight into this obscure lymphoproliferative malignancy. Here, we report one rare case of primary bone DLBCL involving the axial skeleton in a 37-year-old female.

Spontaneous resolution of untreated diffuse large B-cell lymphoma of maxillary bone after incisional biopsy

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of lymphomas which require multiagent therapy for remission induction and are associated with relapse in more than 40% of patients. Spontaneous remission of diffuse large B-cell lymphoma (DLBCL) is a rare occurrence.

Primary Low-Grade B-Cell Lymphoma of Skull With Translocation Between Immunoglobulin and Interferon Regulatory Factor 4 Genes

Low-grade B-cell lymphoma with immunoglobulin ( IG) and interferon regulatory factor 4 ( IRF4) gene rearrangement is extremely rare, with only 4 cases being previously reported. In this article, we report one additional case that arises from the skull and review the literature. The patient was a 69-year-old man who presented with recurrent and disabling vertigo and was found to have a 5.0 × 1.7 cm lesion within the left posterior parietal bone. Histological examination revealed a bone lesion with diffuse lymphoid infiltrate comprising of mostly small lymphocytes with scant cytoplasm, slightly irregular nuclei and inconspicuous nucleoli, and scattered larger cells resembling prolymphocytes and paraimmunoblasts. Immunohistochemical studies showed that the neoplastic cells were positive for CD20, CD79a, PAX5, CD23, CD43, BCL-2, BCL-6, MUM-1, LEF-1, and IgM and negative for CD5, CD10, cyclinD1, SOX11, and IgD. Flow cytometric analysis identified CD5 negative and CD10 negative monoclonal B cells with lambda light chain restriction. Fluorescence in situ hybridization analysis revealed del(13q) abnormality, but was negative for IGH/BCL2, IGH/CCND1, and BIRC3/MALT1 translocations. Next-generation sequencing identified IGK-IRF4 rearrangement and BRD4 E1113 del abnormalities. Given a low clinical stage (IE) of the disease, the patient did not receive additional treatments and was free of disease at 1 year after the diagnosis.

Extranodal Diffuse Large B Cell Lymphoma: Molecular Features, Prognosis, and Risk of Central Nervous System Recurrence

OPINION STATEMENT

Diffuse large B cell lymphoma (DLBCL) arises from extranodal organs in about 30% of cases. Its prognosis and risk of recurrence in the central nervous system (CNS) vary according to the primary site of origin. Recent studies begin to clarify these differences using molecular classification. Testicular, breast, and uterine DLBCL (as well as possibly primary cutaneous DLBCL, leg-type) share a high prevalence of the non-germinal center B cell (non-GCB) phenotype and the MYD88/CD79B-mutated (MCD) genotype. These biologic features, which resemble primary CNS lymphoma, may underlie their stage-independent propensity for CNS involvement. Management of these lymphomas should involve CNS prophylaxis, preferably using systemic high-dose methotrexate to prevent intraparenchymal recurrence. Involvement of the kidneys, adrenal glands, ovary, bone marrow, lung, or pleura usually indicates disseminated disease, conferring worse prognosis. Involvement of these sites is often associated with high CNS-International Prognostic Index (IPI), concurrent MYC and BCL2 or BCL6 rearrangements, or intravascular lymphoma-risk factors warranting CNS prophylaxis. In contrast, craniofacial, thyroid, localized bone, or gastric lymphomas have a variable prevalence of the non-GCB phenotype and lack MYD88 mutations. Their outcomes with standard immunochemotherapy are excellent, and the risk of CNS recurrence is low. We recommend individualized consideration of CNS prophylaxis based on the CNS-IPI score and anatomical proximity in cases of epidural, orbital, or skull involvement. Rituximab-containing immunochemotherapy is a standard approach for all extranodal DLBCLs. Surgery is no longer required for any primary site, but routine consolidative radiation therapy is recommended for testicular lymphoma. Radiation therapy also appears to be associated with better progression-free survival in primary bone DLBCL. Future studies should better distinguish primary from secondary sites of extranodal involvement, and investigate the association of newly identified genotypes with the risk of CNS or systemic recurrence.