Post-transplant lymphoproliferative disorders: clinicopathological analysis of 43 cases in a single center, 1990-2009

Single-center "Argentine" analysis of post-transplant lymphoproliferative disorders: incidence, histopathological characteristics and EBV status

INTRODUCTION

Post-transplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of lymphoid proliferations occurring after solid organ or bone marrow transplantation. The primary aims of our study were to characterize cumulative incidence of PTLDs, clinical and pathological features according to the Epstein-Barr virus (EBV) status and survival.

METHODS

This was a retrospective cohort study on adult and pediatric patients, from January 2001 to December 2017. The cumulative incidence of PTLD was calculated by analyzing all the patients transplanted at our hospital, based on the database of the Organ Donation and Ablation Authority of Argentina (INCUCAI). The Kaplan-Meier method was used to plot the survival.

RESULTS

Fifty-eight cases of biopsy-confirmed PTLD were identified and 12 cases of clinical data were incomplete and these patients were excluded. The median age at the time of the PTLD diagnosis was 17.5 years (interquartile range [IQR] 9 - 57). The median interval between transplant and PTLD diagnosis was 39 months (IQR 9 - 113). The most commonly transplanted organ was the liver (24 cases, 52.2%), followed by kidney (20 cases, 43.5%). The Epstein-Barr encoding region in situ hybridization (EBER ISH) was positive in 29 (69.8%) of the 43 evaluable biopsies. The PTLD cumulative incidence was 1.84% (95%CI 1.77 - 1.91) for solid organ and 0.84% (95%CI 0.48 - 1.2) for bone marrow transplant patients. The overall survival rate at 5 years was 0.77 (95%CI 0.61 - 0.87). Subgroups by the EBV EBER status, transplant type, PTLD subtype and age group (adult vs. pediatric) showed no statistically significant association with the overall survival.

CONCLUSION

The PTLD incidence was similar to that of previous series and the EBER did not appear as a relevant factor in our patient survival.

Characterization and outcome of post-transplant lymphoproliferative disorders within a collaborative study

Background

Post-transplant lymphoproliferative disorders (PTLD) are heterogeneous lymphoid disorders ranging from indolent polyclonal proliferations to aggressive lymphomas that can arise after solid organ transplantation (SOT) and allogeneic hematopoietic transplantation (allo-HSCT).

Methods

In this multi-center retrospective study, we compare patient characteristics, therapies, and outcomes of PTLD after allo-HSCT and SOT. Twenty-five patients (15 after allo-HSCT and 10 after SOT) were identified who developed PTLD between 2008 and 2022.

Results

Median age (57 years; range, 29-74 years) and baseline characteristics were comparable between the two groups (allo-HSCT vs SOT), but median onset of PTLD was markedly shorter after allo-HSCT (2 months vs. 99 months, P<0.001). Treatment regimens were heterogeneous, with reduction of immunosuppression in combination with rituximab being the most common first-line treatment strategy in both cohorts (allo-HSCT: 66%; SOT: 80%). The overall response rate was lower in the allo-HSCT (67%) as compared to the SOT group (100%). Consequently, the overall survival (OS) trended towards a worse outcome for the allo-HSCT group (1-year OS: 54% vs. 78%; P=0.58). We identified PTLD onset ≤150 days in the allo-HSCT (P=0.046) and ECOG >2 in the SOT group (P=0.03) as prognostic factors for lower OS.

Conclusion

PTLD cases present heterogeneously and pose unique challenges after both types of allogeneic transplantation.

Comparison of Post-Transplantation Lymphoproliferative Disorder Risk and Prognostic Factors between Kidney and Liver Transplant Recipients

Post-transplantation lymphoproliferative disorder (PTLD) is a life-threatening complication of solid organ transplantation (SOT). Its development risk varies among organ graft recipients. In this study, retrospective data were analyzed to compare PTLD’s risk and prognostic factors between adult kidney and liver transplant recipients (KTRs and LTRs, respectively). Over 15 years, 2598 KTRs and 1378 LTRs were under observation at our center. Sixteen KTRs (0.62%) and twenty-three LTRs (1.67%) were diagnosed with PTLD. PTLD developed earlier in LTRs (p < 0.001), SOT patients > 45 years old (p = 0.002), and patients receiving tacrolimus (p < 0.001) or not receiving cyclosporin (p = 0.03) at diagnosis. Tacrolimus use, male sex, and age > 45 years old significantly affected the time of PTLD onset in KTRs (hazard ratio (HR) = 18.6, 7.9 and 5.2, respectively). Survival was longer in LTRs < 45 years old (p < 0.009). LTRs were more likely than KTRs to achieve complete remission (p = 0.039). Factors affecting PTLD development and outcome differ between KTRs and LTRs; thus, these populations should be separately evaluated in future studies.

Clinical features of NK/T-cell EBV-associated LPD manifested as gastrointestinal symptoms in patients with normal immunity: a case report and literature review

Background

Epstein–Barr virus (EBV)-associated NK/T-cell lymphoproliferative disorder (LPD) involving the gastrointestinal tract is rarely observed in individuals with normal immunity. The atypical clinical, colonoscopic manifestations often confuse clinicians, leading to misdiagnosis and delays in the treatment.

Case presentation

Herein, we reported on a single case of a patient with gastrointestinal symptoms. Several colonoscopies showed multiple irregular ulcerations, while biopsies showed colitis with infiltration of neutrophils or lymphocytes. After 2 months follow-up, the patient was diagnosed with the extranodal NK/T-cell lymphoma, nasal type, and was treated with thalidomide. Later on, a second check was performed on his first pathological sample. Immunohistochemistry revealed EBV associated NK/T-cell LPD.

Conclusions

Multiple, multiform, and segmental gastrointestinal ulcers should be an indication for EBV infection, regardless of the presence of fever, lymphadenopathy, and hepatosplenomegaly. If EBV-associated NK/T-cell LPD is considered, serum EBV-DNA should be measured, and the tissue obtained by biopsy should be carefully analyzed for a positive expression of the EBER marker.

Reappraisal of the prognostic value of Epstein-Barr virus status in monomorphic post-transplantation lymphoproliferative disorders-diffuse large B-cell lymphoma

The role of the Epstein-Barr virus (EBV) status in the blood for predicting survival in post-transplantation lymphoproliferative disorders-diffuse large B-cell lymphoma (PTLD-DLBCL) is unknown. We evaluated the prognostic values of pre-treatment EBV-encoded small RNA (EBER) detected with in situ hybridization in tissues and EBV DNA in the whole blood (WB) and plasma in 58 patients with monomorphic PTLD-DLBCL after solid organ transplantation. There were no significant differences in the rates of overall response, complete response, and survival according to EBER EBV and WB EBV status. In contrast, patients with positive plasma EBV DNA had significantly lower rates of overall response (60.0% vs. 94.4%, P = 0.043) and complete response (40.0% vs. 88.9%, P = 0.019) as well as worse progression-free survival (PFS) (P = 0.035) and overall survival (OS) (P = 0.039) compared with patients with negative plasma EBV DNA. In multivariate analysis, plasma EBV DNA positivity was a significantly unfavorable prognostic factor for PFS [hazard ratio (HR) 4.92, 95% confidence interval (CI) 1.22-19.86, P = 0.025] and OS (HR 4.48, 95% CI 1.14-17.63, P = 0.032). Despite small number of 6 patients with plasma EBV positivity, plasma EBV DNA positivity might be more prognostic for survival than EBER or WB EBV DNA positivity in patients with monomorphic PTLD-DLBCL.

Central Nervous System Involvement in Epstein-Barr Virus-Related Post-Transplant Lymphoproliferative Disorders after Allogeneic Hematopoietic Stem Cell Transplantation

Central nervous system (CNS) involvement in Epstein-Barr virus-related post-transplant lymphoproliferative disorders (EBV-PTLDs) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poorly defined. We analyzed the incidence, clinical and pathological characteristics, and impact on outcomes of EBV-PTLDs with CNS involvement (CNS-PTLDs) in 1009 consecutive adult patients undergoing allo-HSCT at a single-center institution. Four hundred eighty-two patients received matched sibling donor (MSD) transplants, 388 umbilical cord blood transplants (UCBTs), 56 matched unrelated donor (MUD) transplants, and 83 haploidentical transplants. We detected 25 cases of biopsy-proven EBV-PTLDs. Of these, nine patients (36%) had CNS-PTLDs: six after UCBT (67%), one after MSD transplantation (11%), one after MUD transplantation (11%), and one after haploidentical transplantation (11%). The 5-year cumulative incidence risk of CNS-PTLDs was 0.9%. Median time from transplant to CNS-PTLDs was 187 days, and all patients had neurological symptoms at diagnosis. Six out of the nine cases (67%) occurred with systemic involvement, and three cases (33%) had isolated CNS involvement. The most frequent histological subtype was monomorphic EBV-PTLD, and laboratory characteristics were similar to EBV-PTLDs without CNS involvement. We observed statistical differences in the rate of positive EBV DNA detection in plasma between isolated CNS-PTLDs (detection in one out of three, 33%) and the rest of the EBV-PTLDs (100%) (P = .01). Treatment strategies included chemotherapy, radiotherapy, and T cell therapy. However, seven out of nine patients died due to progression of the CNS-PTLDs at a median time of 17 days (range, 8 to 163) from diagnosis. The 5-years overall survival in patients who developed CNS-PTLDs was 22% (95% confidence interval [CI], 7% to 75%) and 5-year treatment-related mortality was 78% (95% CI, 51% to 100%), with no statistically significant differences between CNS-PTLDs and the rest of the EBV-PTLDs. In conclusion, despite advances in EBV monitoring and treatment strategies, CNS-PTLDs remain an uncommon but serious complication after allo-HSCT, with very poor prognosis.

Epstein-Barr viral load monitoring for diagnosing post-transplant lymphoproliferative disorder in pediatric liver transplant recipients

This study aimed to investigate the incidence of PTLD in pediatric liver transplant recipients and the risk factors for the development of PTLD. We also determined clinically useful quantitative EBV PCR parameters for aiding in the diagnosis of EBV-associated PTLD in the pediatric liver transplant recipients at our institute. We reviewed children < 18 years old who had undergone liver transplantations and quantitative analysis of whole blood EBV load at our institute from January 2006 to March 2015. A total of 142 liver transplant recipients were included, and their median age was 1.5 years. Clinically significant high-level EBV DNAemia ≥ 10 000 copies/mL at least twice was observed in 53.5% and PTLD occurred in 9.9%. Among PTLD group, graft failure and mortality rate were as high as 21.4% and 14.3%, respectively. Deceased donor, presence of high-level EBV DNAemia, and primary CMV infection following transplant were associated with an increased risk for PTLD in the multivariate analysis. The peak titer at 10 875 copies/mL could be used as a cutoff value with a sensitivity of 92.9% and a specificity of 37.9%; the rate of increase in EBV load suggested a sensitivity of 64.3% and a specificity of 70.9% at the cutoff value of 44 000 copies/mL/week. In conclusion, the incidence of PTLD following liver transplant in children was as high as 10%. PTLD is associated with significant morbidity and mortality. Close monitoring of EBV DNAemia is crucial for the early diagnosis and proper treatment of PTLD in pediatric liver transplant recipients.

Epstein-Barr virus reactivation after allogeneic hematopoietic stem cell transplantation: multifactorial impact on transplant outcomes

Epstein-Barr virus (EBV) reactivation after allogeneic hematopoietic cell transplantation (allo-HCT) is one of the major concerns that may lead to fatal EBV diseases. However, updated data are needed because of the remarkable evolution of the HCT protocol and donor selection. We conducted a retrospective study that enrolled 890 allo-HCT recipients. Independent risk factors for EBV reactivation were use of antithymocyte globulin, haploidentical donor, and the presence of chronic graft-versus-host disease. The cumulative incidence of EBV reactivation was 2.9%, 11.7%, 27.3%, and 41.9% for patients with 0, 1, 2, and 3 risk factors, respectively (P < 0.001). Posttransplant lymphoproliferative disorders (PTLDs) occurred in seven patients. EBV reactivation was associated with inferior survival in recipients who survived more than 2 years post-HCT (P < 0.001) but might time-dependently benefit those patients with malignancies by decreasing relapse incidence (P = 0.046). A decreased relapse incidence was observed 1 year after HCT for recipients at first or second remission (P = 0.042) and in the first year post-HCT for recipients with advanced diseases (P = 0.032). We concluded that with current management, PTLDs were efficiently controlled, but EBV reactivation still had a multifactorial impact on transplant outcomes. Multicenter prospective studies are warranted to validate these findings.

Post-transplantation lymphoproliferative disease in pediatric liver recipients in Taiwan

BACKGROUND

Post-transplantation lymphoproliferative disorder (PTLD) is a heterogeneous, potentially life-threatening complication after liver transplantation in children. In this study, the disease characteristics, outcomes, and prognostic factors of PTLD were investigated.

METHODS

A retrospective, observational study was conducted on 16 pediatric liver transplant (LT) recipients who developed PTLD between February 2001 and December 2013 at a tertiary referral center in Taiwan. The disease characteristics and treatment outcomes of the patients were analyzed.

RESULTS

The median time from liver transplantation to the development of PTLD was 8 months. Early onset (<1 year post-transplantation) PTLD constituted 62.5% of the cases. PTLD location was frequently extranodal (81.3%) and mostly involved the gastrointestinal tract (68.8%). Histopathologic findings showed polymorphic PTLD in six cases (37.5%), diffuse large B-cell lymphoma in five cases (31.3%), and Burkitt's PTLD in two cases (12.5%). Early lesions in PTLD, T-cell lymphoma, and Hodgkin's lymphoma were observed in one case each (6.3%). Overall survival at 1- and 5-years post-PTLD diagnosis was 87.5% and 79.5%, respectively. St Jude's classification stage IV disease was associated with poor survival (hazard ratio [HR] = 13.37, P = 0.037). Two patients (12.5%) had chronic rejection after the treatment for PTLD and one patient (6.3%) developed graft failure.

CONCLUSION

PTLD is a major complication in pediatric LT recipients, but long-term survival is possible in most cases with an adequate treatment strategy. Stage IV disease is a major risk factor for poor survival in pediatric PTLD patients. During the management of PTLD, the possibility of chronic rejection and even graft failure should be considered.

Post-transplant lymphoproliferative disorders after solid organ and hematopoietic stem cell transplantation

Post-transplant lymphoproliferative disorders (PTLD) are a rare complication after both solid organ (SOT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this single center retrospective study, we compared clinical, biological, and histological features, and outcomes of PTLD after both types of transplant. We identified 82 PTLD (61 after SOT and 21 after allo-HSCT). The presence of B symptoms, Waldeyer ring, spleen, central nervous system, and liver involvement, and advanced Ann-Arbor stage were more frequent in allo-HSCT recipients. PTLD had an earlier onset in allo-HSCT than in SOT cohort (4 vs. 64 months, p < .0001). PTLD was EBV-positive in 100% of allo-HSCT, in contrast to 47% of SOT (p = .0002). Four years after PTLD diagnosis, median overall survival was 32% (95% CI, 22-48) and 10% (95% CI, 2-49) in SOT and allo-HSCT recipients, respectively (p = .002). In conclusion, the clinical presentation and the outcome of PTLD varies greatly depending on the type of transplant.

No Increased Risk of Posttransplant Lymphoproliferative Disorder Following Alemtuzumab Induction in Kidney Transplant

OBJECTIVES

Posttransplant lymphoproliferative disorder is a known complication of solid-organ transplant. The use of depleting induction agents has demonstrated varying associations with incidence of posttransplant lymphoproliferative disorder. Alemtuzumab, a depleting induction agent for kidney transplant patients, has shown promising results in reducing the risk of acute rejection and graft loss in the first year. Its unique mechanism of depleting both T-cell and B-cell populations may be beneficial in preventing the occurrence of posttransplant lymphoproliferative disorder.

MATERIALS AND METHODS

We examined the known risk factors for posttransplant lymphoproliferative disorder in the setting of alemtuzumab induction to determine whether incidence increases with this induction agent. We reviewed medical records of all alemtuzumab-induced kidney transplants from March 2006 to November 2015.

RESULTS

Of the 675 transplant patients who received alemtuzumab induction, 10 developed posttransplant lymphoproliferative disorder, with a cumulative incidence rate of 1.5%. All diagnosed patients had several known risk factors associated with posttransplant lymphoproliferative disorder: 7 with advanced age over 60 years, 5 being cytomegalovirus-negative recipients, and all 10 donor kidneys being male patients and Epstein-Barr virus positive before transplant.

CONCLUSIONS

The incidence rate seen in our patient population was within the range of the average in the United States but far lower than the incidence rates associated with other induction agents. Alemtuzumab is associated with a lower cumulative incidence rate of posttransplant lymphoproliferative disorder compared with published reports of other induction treatments.

Posttransplantation lymphoproliferative disorder after pediatric solid organ transplantation: experiences of 20 years in a single center

PURPOSE

To evaluate the clinical spectrum of posttransplantation lymphoproliferative disorder (PTLD) after solid organ transplantation (SOT) in children.

METHODS

We retrospectively reviewed the medical records of 18 patients with PTLD who underwent liver (LT) or kidney transplantation (KT) between January 1995 and December 2014 in Seoul National University Children's Hospital.

RESULTS

Eighteen patients (3.9% of pediatric SOTs; LT:KT, 11:7; male to female, 9:9) were diagnosed as having PTLD over the last 2 decades (4.8% for LT and 2.9% for KT). PTLD usually presented with fever or gastrointestinal symptoms in a median period of 7 months after SOT. Eight cases had malignant lesions, and all the patients except one had evidence of Epstein-Barr virus (EBV) involvement, assessed by using in situ hybridization of tumor tissue or EBV viral load quantitation of blood. Remission was achieved in all patients with reduction of immunosuppression and/or rituximab therapy or chemotherapy, although 1 patient had allograft kidney loss and another died from complications of chemotherapy. The first case of PTLD was encountered after the introduction of tacrolimus for pediatric SOT in 2003. The recent increase in PTLD incidence in KT coincided with modification of clinical practice since 2012 to increase the tacrolimus trough level.

CONCLUSION

While the outcome was favorable in that all patients achieved complete remission, some patients still had allograft loss or mortality. To prevent PTLD and improve its outcome, monitoring for EBV infection is essential, which would lead to appropriate modification of immunosuppression and enhanced surveillance for PTLD.

Posttransplant lymphoproliferative disease and survival in adult heart transplant recipients

BACKGROUND

The influence of posttransplant lymphoproliferative disease (PTLD) on long-term survival after heart transplantation (HTx) in adult recipients needs better characterization.

METHODS

The United Network for Organ Sharing database was queried from 2006 to 2015 to compare survival between adult HTx recipients with and without PTLD. Cox proportional hazards models were used to analyze the primary outcome of survival, and competing-risks regression was used to analyze the outcome of PTLD development.

RESULTS

A total of 14,487 HTx recipients who had data on PTLD were included in univariate Cox analysis and Kaplan-Meier survival function, while 10,422 were included in multivariable Cox analysis and 162 selected for a matched-pairs sample after matching on the propensity of developing PTLD. The cohort included 120 patients who were diagnosed with PTLD. Onset of PTLD, treated as a time-varying covariate, was adversely associated with survival in univariate (HR=4.953; 95% CI: 3.768, 6.511; p<0.001) and multivariable (HR=3.849; 95% CI: 2.669, 5.552; p<0.001) Cox proportional hazards models. Cox regression stratified on matched pairs of PTLD cases and non-PTLD controls confirmed the risk for death associated with PTLD onset (HR=2.667; 95% CI: 1.043, 6.815; p=0.040).

CONCLUSIONS

PTLD onset negatively influenced survival in adult HTx recipients, whereas no characteristics predisposing patients to PTLD development were identified in multivariate analysis.

Post-transplant lymphoproliferative disorders: from epidemiology to pathogenesis-driven treatment

Post-transplant lymphoproliferative disorders (PTLDs) represent the most severe complication of both solid organ and hematopoietic stem cell transplantation. The Epstein-Barr Virus (EBV) is the main driver of PTLD, particularly those occurring early after transplantation. EBV-driven malignancies are associated with selective expression of latent viral proteins, but uncontrolled lytic replication may favor early phases of cell transformation. Besides immunodepression, persistent immune activation and chronic inflammation play an important role in both virus reactivation and expansion of EBV-infected B cells. EBV-induced immortalization requires the expression of telomerase. TERT, the rate-limiting component of the telomerase complex, is central in the switch from the lytic to the latent viral program, and TERT inhibition induces the EBV lytic cycle and cell death. Immunotherapy and combination of EBV lytic cycle inducers with antiviral drugs are promising strategies to improve the treatment of PTLD patients. This review is aimed at providing an update on the intriguing association between EBV and PTLD, mainly focusing on cases arising after kidney and liver transplantation, which account for the vast majority of transplants.

Epstein-Barr virus (EBV)--associated posttransplant lymphoproliferative disorder appearing as mandibular gingival ulcers

Posttransplant lymphoproliferative disorders (PTLDs) comprise a spectrum of complications that affect immunocompromised patients following hematopoietic stem cell transplantation or solid organ transplantation. Its incidence varies depending on the transplanted organ, occurring in approximately 2.3% of kidney transplantations. A 31-year-old woman was referred to the Dental Clinic of the State University of Western Paraná for evaluation of an oral lesion. Her medical history revealed a previous diagnosis of hypertension, Epstein-Barr virus (EBV) seropositivity, and kidney transplantation 12 years prior. She was under standard immunosuppressive therapy. Intraoral examination identified a gingival necrotic lesion with extension to the posterior right lower alveolar bone. An incisional biopsy was performed. Histologic examination showed lymphocytic proliferation of cells with small and hyperchromatic nuclei, atypical mitosis, and cells with large and pale nuclei showing prominent nucleoli permeating connective tissue, muscle fibers, and adipocytes. Correlation of clinical, histologic, and immunohistochemical findings led to a diagnosis of polymorphic EBV-associated PTLD rich in B and T cells.

Pattern analysis of Epstein-Barr virus viremia and its significance in the evaluation of organ transplant patients suspected of having posttransplant lymphoproliferative disorders

OBJECTIVES

To explore posttransplant lymphoproliferative disorder (PTLD) cases associated with Epstein-Barr virus (EBV).

METHODS

We retrospectively reviewed the EBV DNA quantitation data of 9,779 blood samples from 740 transplant patients and their associations with PTLD.

RESULTS

EBV viremia occurred more frequently in patients with PTLD (85.4%) in comparison with patients without PTLD (38.3%; P < .0001). Patients with PTLD demonstrated significantly higher first positive results, higher peak levels, and a higher rate of increase in EBV viral load compared with patients without PTLD (P = .002, P < .0001, and P < .0001, respectively). However, in the multivariate analysis, only the peak level was associated with the development of PTLD. In particular, within hematopoietic stem cell recipients, the peak level able to diagnose PTLD was an area under the receiver operating characteristic curve of 0.806.

CONCLUSIONS

We believe that pattern analysis of EBV DNA quantitation results could lead to the early diagnosis and timely treatment of PTLD.

Post-transplant lymphoproliferative disorders in liver transplant recipients: a clinicopathological study

BACKGROUND AND AIMS

Complications after liver transplantation are major factors that determine the prognosis of patients. In this study, we aimed at investigating an important though less frequently occurring complication, post-transplant lymphoproliferative disorders (PTLD), in a single institution after liver transplantation.

METHODS

15 cases with a diagnosis of PTLD in post-liver transplant patients were retrieved from our archive and the clinicopathological features reviewed.

RESULTS

The overall incidence of PTLD was 2.3% (n=15/658), and the incidence was much higher in the paediatric than the adult age groups, being 11.1% (9/81) and 1% (6/577), respectively. The median time of presentation was 16 months after transplantation (occurrence time ranging from 2 to 87 months after transplantation). Lymph nodes, gastrointestinal tract and graft liver were the commonest sites of involvement. 11 cases were classified as monomorphic PTLD according to WHO classification and the majority (n=10/11) of them were of B cell differentiation. 12 of the total 15 PTLD cases showed a positive result for Epstein-Barr virus-encoded RNAs with in situ hybridisation. Eight patients were alive at the time of review, and two of them suffered from recurrence of the PTLD. Among the seven patients who died, six succumbed within 1 year from the diagnosis of PTLD.

CONCLUSIONS

Despite its relative rarity as a complication for liver transplantation, PTLD imposes significant effects on the morbidity, mortality and treatment implications in postliver transplant patients. The clinicopathological data would hopefully provide better insight into the surveillance and management for susceptible patients.

Epidemiologic overview of malignant lymphoma

Malignant lymphoma encompasses a wide variety of distinct disease entities. It is generally more common in developed countries and less common in developing countries. The East Asia region has one of the lowest incidence rates of malignant lymphoma. The incidence of malignant lymphoma around the world has been increasing at a rate of 3-4% over the last 4 decades, while some stabilization has been observed in developed countries in recent years. The reasons behind this lymphoma epidemic are poorly understood, although improving diagnostic accuracy, the recent AIDS epidemic, an aging world population and the increasing adoption of cancer-causing behaviors are suggested as contributing factors. Etiologies of malignant lymphoma include infectious agents, immunodeficiency, autoimmune disease, exposure to certain organic chemicals, and pharmaceuticals. The distribution of many subtypes exhibit marked geographic variations. Compared to the West, T/natural killer (NK) cell lymphomas (T/NK-cell lymphoma) and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) are relatively more common, whereas other B-cell lymphomas, particularly follicular lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, are less common in Asia. Some subtypes of T/NK-cell lymphomas defined by Epstein-Barr virus association are predominantly Asian diseases, if not exclusively so. Both ethnic and environmental factors play roles in such diversity. In this review, we discuss the geographic distribution and etiology of malignant lymphoma, as well as the trend.