Lymphoma-like Lesions Research Articles

Development of Aging-Related Emphysematous and Lymphoma-Like Lesions is Enhanced by the Lack of Secretoglobin 3A2 in Mouse Lungs.

BackgroundSecretoglobin (SCGB) 3A2 is a novel bioactive molecule with anti-inflammatory and anti-fibrotic activities. SCGB3A2 also promotes the maturation of bronchial divergence and the lungs during embryonic development. However, much remains unknown concerning the roles of SCGB3A2 in diseases associated with aging.MethodsThe lungs of Scgb3a2-knockout (KO) mice and their wild-type (WT) littermates were subjected to histological analysis, Victoria blue staining to evaluate of elastic fibers, and lung morphometric analysis during the postnatal period (birth to 8 weeks) and during aging (8 weeks to 2 years). Their spleens were also histologically evaluated. The expression of lung surfactant protein (SP) mRNAs was examined by quantitative reverse transcriptase-polymerase chain reaction. RNA sequencing (RNAseq) analysis was performed on 3-month-old KO and WT mouse lungs.ResultsThe alveolar spaces of KO mice continuously expanded between 0.5 and 2 years of age, accompanied by increases of the mean linear intercept and destructive index. KO mouse lungs displayed inflammation associated with lymphocyte aggregate starting at 1 year of age, and the inflammation was worse than that of WT mouse lungs. A high number of lymphoma-like cells were presented in 2-year-old KO mouse lungs. White pulp fusion was detected in the spleens of both WT and KO mice older than 0.5 years; however, the fusion was more severe in KO mice than in WT mice. The expression of surfactant protein (SP)-A, SP-B, SP-C, and SP-D mRNAs in KO mouse lungs decreased with age, and after 1 year of age, the expression of most SPs was significantly lower in KO mice than in WT mice. RNAseq demonstrated that the expression of immune system-related genes was highly altered in KO mouse lungs.ConclusionSCGB3A2 may be required for maintaining homeostasis and immune activity in the lungs during aging. SCGB3A2 deficiency might increase the risk of emphysema of the lung.

Florid Lymphoid Hyperplasia or Lymphoma-like Lesion of the Lower Genital Tract: A 35-Year Literature Review in View of the New WHO Classification.

Florid lymphoid hyperplasias of the lower female genital tract, also known as pseudolymphoma or lymphoma-like lesions, are benign lesions displaying histologic features which mimic aggressive B-cell lymphomas. Initially described by Young and colleagues in 1985, fewer than 100 cases have been published, making this lesion rather uncommon and subject to misdiagnoses. However, given that this entity has now been included in the World Health Organization's most recent classification, greater clarity would be beneficial for pathologists and physicians. Thus, our report aims to review these entities and provide all available data. We reviewed the available literature according to PRISMA guidelines. We found that lymphoma-like lesions, regardless of their localization, display numerous superficial lymphoid B cells admixed with a polymorphic small lymphocytic and plasmocytic background and, sometimes, superficial ulceration. Large lymphoid cells show prominent nucleoli and mitotic figures. Immunohistochemistry can usually exclude large cell lymphomas, such as high-grade follicular lymphoma and Burkitt lymphoma, when a starry sky pattern is found, as well as Hodgkin Lymphoma; however, the exclusion of diffuse large B-cell lymphoma or marginal zone lymphoma is more difficult. Explorations seeking infectious agents may show Epstein-Barr virus or, rarely, Borrelia burgdorferi involvement. Molecular study occasionally finds a monoclonal B-cell population, but without the subsequent follow-up which would otherwise be worrisome. Despite its somewhat aggressive histologic features, the benignity of this entity must be highlighted to avoid misdiagnosis and complications due to overtreating.

Analysis of proliferative lesions of haematopoietic and lymphoid tissue in the female productive tract

Objective: To study the clinicopathologic features, diagnosis and differential diagnosis of tumors of haematopoietic and lymphoid tissue in the female productive tract. Methods: Eleven cases of myeloid sarcoma and leukemia, 9 of non Hodgkin lymphoma (NHL) , 13 of cervical lymphoma-like lesions were selected from Peking University People's Hospital from January 2006 to August 2017. According to WHO classification of tumors of haematopoietic and lymphoid tissues (2008) and updated classification(2016), the cases were studied by microscopy, immunohistochemistry and in situ hybridization. Results: In 20 cases of tumors of haematopoietic and lymphoid tissue, the mean and median age was 48.5 and 56 years old (range: 16-77 years old) . In cases of lymphoma-like lesion of uterine cervix, the mean and median age was 45.9 and 48 years old (range: 23-62 years old) . The patients with neoplasm present as fever, fatigue, hypogastralgia, colporrhagia and mass etc. Eight cases had history of acute myeloid leukemia, and 3 had myeloid leukemia while pregnancy. One case of chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) had history of ovary small cell carcinoma and high grade serous carcinoma resected with chemotherapy. One case of diffuse large B cell lymphoma (DLBCL) had history of renal transplantation. Lactic dehydrogenase (LDH) was elevated in 9 cases (9/18) . The cases of lymphoma-like lesion present as contact bleeding in most cases and all located in cervix. Four cases of neoplasm located in vulva, 1 in vagina, 4 in cervix, 4 in uterine corpus, 8 in ovary and 2 in placenta. Clinical staging of NHL: 4 case was stageⅠ, 1 case of stageⅢ, and 4 cases of stage Ⅳ. Pathological morphology: 9 cases were myeloid sarcoma, 2 cases were placenta invaded by myeloid leukemia. Six cases were DLBCL, and 1 case was CLL/SLL, 1 case was mucosa associated lymphoid tissuse lymphoma (MALToma) , and 1 case was anaplastic large cell lymphoma. Resected mass, chemotherapy was performed in tumors of haematopoietic and lymphoid tissue. Five cases of myeloid sarcoma and 2 of NHL died. In 13 cases of lymphoma-like lesion of uterine cervix, the general condition was good as following up. Conclusions: The clinical history, pathological morphology and immunohistochemistry are very important for diagnosing tumors of haematopoietic and lymphoid tissue in the female productive tract. Resection with chemotherapy is recommended in treatment. The prognosis of lymphoma-like lesion of uterine cervix is good, and should be differentiated from lymphoma.

MALT Lymphoma-Like Gastric Mucosal Lesion Disappeared by Eradication of Helicobacter Suis

MALT Lymphoma-Like Gastric Mucosal Lesion Disappeared by Eradication of Helicobacter Suis

Gastric de novo Muc13 expression and spasmolytic polypeptide-expressing metaplasia during Helicobacter heilmannii infection.

Helicobacter heilmannii is a zoonotic bacterium that has been associated with gastric disease in humans. In this study, the mRNA expression of mucins in the stomach of BALB/c mice was analyzed at several time points during a 1-year infection with this bacterium, during which gastric disease progressed in severity. Markers for acid production by parietal cells and mucous metaplasia were also examined. In the first 9 weeks postinfection, the mRNA expression of Muc6 was clearly upregulated in both the antrum and fundus of the stomach of H. heilmannii-infected mice. Interestingly, Muc13 was upregulated already at 1 day postinfection in the fundus of the stomach. Its expression level remained high in the stomach over the course of the infection. This mucin is, however, not expressed in a healthy stomach, and high expression of this mucin has so far only been described in gastric cancer. In the later stages of infection, mRNA expression of H(+)/K(+)-ATPase α/β and KCNQ1 decreased, whereas the expression of Muc4, Tff2, Dmbt1, and polymeric immunoglobulin receptor (pIgR) increased starting at 16 weeks postinfection onwards, suggesting the existence of spasmolytic polypeptide-expressing metaplasia in the fundus of the stomach. Mucous metaplasia present in the mucosa surrounding low-grade mucosa-associated lymphoid tissue (MALT) lymphoma-like lesions was also histologically confirmed. Our findings indicate that H. heilmannii infection causes severe gastric pathologies and alterations in the expression pattern of gastric mucins, such as Muc6 and Muc13, as well as disrupting gastric homeostasis by inducing the loss of parietal cells, resulting in the development of mucous metaplasia.

Florid reactive lymphoid hyperplasia (lymphoma-like lesion) of the uterine cervix

Lymphoma-like lesion (LLL) of the female genital tract is an older term in the literature that describes a florid reactive lymphoid proliferation that can be misinterpreted as lymphoma. Multiple causes of LLL have been suggested but most cases remain unexplained. We describe the clinicopathologic features of 6 patients with LLL involving the uterine cervix. Five patients presented with abnormal Papanicolaou test (Pap smear), and 3 patients had a biopsy procedure performed prior to detection of LLL in a loop electrosurgical excision procedure (LEEP). In each specimen, surface epithelial erosion was associated with a superficial, polymorphous lymphoid infiltrate with numerous scattered large cells, without cellular necrosis or sclerosis. Squamous dysplasia was present in 4 patients. Immunohistochemical studies revealed a mixed population of B- and T-lymphoid cells. T-cells were more numerous but B-cells and formed aggregates or sheets in areas. The large cells were predominantly B-cells positive for CD20 and negative for CD3 in all cases. CD30 was positive 3 cases, and Epstein-Barr virus-encoded RNA was positive in 3 cases. Assessment for clonality in 1 patient using polymerase chain reaction (PCR) methods revealed monoclonal immunoglobulin heavy chain (IgH) gene rearrangements. At last clinical follow-up there was no evidence of progressive or systemic disease. We conclude that LLL of the cervix has a number of etiologies and that a prior surgical procedure, present in 3 patients in this study, is another possible etiology. As has been reported by others, monoclonal IgH gene rearrangements can be detected in this entity which has a benign clinical course.

Helicobacter suis Causes Severe Gastric Pathology in Mouse and Mongolian Gerbil Models of Human Gastric Disease

Background“Helicobacter (H.) heilmannii” type 1 is the most prevalent gastric non-H. pylori Helicobacter species in humans suffering from gastric disease. It has been shown to be identical to H. suis, a bacterium which is mainly associated with pigs. To obtain better insights into the long-term pathogenesis of infections with this micro-organism, experimental infections were carried out in different rodent models.Methodology/Principal FindingsMongolian gerbils and mice of two strains (BALB/c and C57BL/6) were infected with H. suis and sacrificed at 3 weeks, 9 weeks and 8 months after infection. Gastric tissue samples were collected for PCR analysis, histological and ultrastructural examination. In gerbils, bacteria mainly colonized the antrum and a narrow zone in the fundus near the forestomach/stomach transition zone. In both mice strains, bacteria colonized the entire glandular stomach. Colonization with H. suis was associated with necrosis of parietal cells in all three animal strains. From 9 weeks after infection onwards, an increased proliferation rate of mucosal epithelial cells was detected in the stomach regions colonized with H. suis. Most gerbils showed a marked lymphocytic infiltration in the antrum and in the forestomach/stomach transition zone, becoming more pronounced in the course of time. At 8 months post infection, severe destruction of the normal antral architecture at the inflamed sites and development of mucosa-associated lymphoid tissue (MALT) lymphoma-like lesions were observed in some gerbils. In mice, the inflammatory response was less pronounced than in gerbils, consisting mainly of mononuclear cell infiltration and being most severe in the fundus.Conclusions/Significance H. suis causes death of parietal cells, epithelial cell hyperproliferation and severe inflammation in mice and Mongolian gerbil models of human gastric disease. Moreover, MALT lymphoma-like lesions were induced in H. suis-infected Mongolian gerbils. Therefore, the possible involvement of this micro-organism in human gastric disease should not be neglected.

Concurrent classical Hodgkin lymphoma and plasmablastic lymphoma in a patient with chronic lymphocytic leukemia/small lymphocytic lymphoma treated with fludarabine: a dimorphic presentation of iatrogenic immunodeficiency-associated lymphoproliferative disorder with evidence suggestive of multiclonal transformability of B cells by Epstein-Barr virus

A small fraction of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma develop Epstein-Barr virus-positive B-cell lymphoproliferative disorders. These Epstein-Barr virus-B-cell lymphoproliferative disorders are thought to be related to immune suppression induced by fludarabine/other chemotherapeutic regimens. As in other immunodeficiency-associated lymphoproliferative disorders, these disorders demonstrate a heterogeneous histological spectrum that ranges from polymorphic to monomorphic to classical Hodgkin lymphoma-like lesions. We report a case of concurrent classical Hodgkin lymphoma and plasmablastic lymphoma in a patient with chronic lymphocytic leukemia/small lymphocytic lymphoma treated with fludarabine. Both classical Hodgkin lymphoma and plasmablastic lymphoma were positive for Epstein-Barr virus-encoded RNA, whereas classical Hodgkin lymphoma was also positive for Epstein-Barr virus- latent membrane protein 1, suggesting a different viral latency. Immunoglobulin gene rearrangement studies demonstrated distinct clones in the plasmablastic lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma. These findings suggest biclonal secondary lymphomas associated with iatrogenic immunodeficiency. Epstein-Barr virus-B-cell lymphoproliferative disorders in the setting of chronic lymphocytic leukemia/small lymphocytic lymphoma, in particular those arising after chemotherapy, should be separated from true Richter's transformation, and be categorized as (iatrogenic) immunodeficiency-associated lymphoproliferative disorder.

Florid Reactive Lymphoid Hyperplasia of the Lower Female Genital Tract (Lymphoma-like Lesion): A Benign Condition That Frequently Harbors Clonal Immunoglobulin Heavy Chain Gene Rearrangements

Lymphoma-like lesions (LLL) of the lower female genital tract are florid reactive inflammatory processes that mainly occur in women in their reproductive years. Histologically, they are characterized by a dense lymphoid infiltrate with admixed large cells that is often suspicious for lymphoma. In contrast to lymphoma, however, they are superficial lesions that typically show surface erosion and a mixed lymphoid infiltrate and do not have evidence of a mass, deep invasion, or prominent sclerosis. With the advent of widespread molecular genetic testing, it would seem that LLLs should be polyclonal helping make the correct diagnosis. However, we have found cases with morphologic and immunophenotypic features of LLLs and evidence of clonal rearrangement of the immunoglobulin heavy chain (IGH) gene, potentially leading to misdiagnosis. We examined the clinicopathologic features and outcome of 12 patients with LLL (9 in the cervix and 3 in the endometrium). The patients ranged in age from 18 to 54 (median 37) years and came to medical attention because of squamous dysplasia (8 patients), vaginal bleeding (3), or adnexal mass (1). One patient had an endocervical polyp, but otherwise none had a discrete mass. The specimens contained a dense, polymorphous inflammatory infiltrate, commonly associated with mucosal erosion. Immunohistochemical studies showed a mixture of B and T cells without immunoglobulin light chain restriction. Four cases (all cervical) had a clonal IGH gene rearrangement by PCR. There was no evidence of lymphoma on staging or on follow-up in any patient, including the 4 patients with clonal IGH rearrangement, after a mean follow-up of 3.5 years (range: 4 mo to 13 y). In summary, we describe 12 patients with LLL of the lower female genital tract. Four of the 9 cases (44%) analyzed by PCR had a clonal IGH gene rearrangement. The clinical and pathologic features of these cases suggest that a clonal IGH rearrangement in this setting does not warrant a diagnosis of lymphoma. Careful correlation of clinical, histologic, immunophenotypic, and genetic features is required to avoid misdiagnosis and inappropriate treatment. Routine microscopic findings and detailed clinical information remain paramount in establishing the correct diagnosis.

Detection of lymphoma-like lesions in the liver of hepatitis C virus-infected patients

HCV感染是导致慢性肝炎、肝硬化和肝细胞肝癌的主要原因之一.据估计全球约1.7亿人感染HCV,约70%转为慢性,其中又有约20%～30%在10～30年发展为肝硬化,进而可导致肝细胞肝癌的发生。

Sonography of Biopsy-Proven Langerhans Cell Histiocytosis in Lymph Nodes of the Neck

The purpose of this series is to describe the sonographic findings of lymph nodes of the neck involved by Langerhans cell histiocytosis (LCH). We reviewed and interpreted available images of lymph nodes in patients with cervical lymphadenopathies involved by LCH for the past decade. In all patients, each abnormal lymph node was pathologically confirmed by the use of a sonographically guided core needle biopsy or an incisional biopsy. We characterized 3 different kinds of imaging findings for cervical lymph nodes involved by LCH: (1) a lymphomalike lesion, (2) a lesion similar to reactive lymphadenopathy, and (3) a cystic lymph node. There was no specific imaging finding to diagnose lymphadenopathy involved by LCH. In our study, we characterized 3 different imaging patterns of lymph node involvement by LCH. This study represents an initial step to organize specific findings for LCH.

Endométrite chronique pseudolymphomateuse

Chronic endometritis is a rare entity characterized by an endometrial plasmocytic infiltrate. The lymphoid infiltrate may be abundant and simulate a lymphoma of the uterus. We report two cases of lymphoma-like lesions of the endometrium in two postmenopausal women of 79 and 89 year-old, who presented with abundant vaginal discharge. Ultrasound examination revealed in both cases an intrauterin polypoid lesion. Histologically, a predominantly plasmocytic infiltrate was seen in the endometrium destroying endometrial glandes and extending into the superficial myometrium, in the first case. Immunohistochemical study showed a polymorphic lymphoid infiltrate with a predominance of Tcells. Molecular study revealed a polyclonalB cell population, distinguishing the lesion from a marginal zone lymphoma. Lymphoma-like lesions of female genital tract must be distinguished from malignant lymphoma that rarely occurs in this site.

Transformation of vulvar pseudolymphoma (lymphoma‐like lesion) into a marginal zone B‐cell lymphoma of labium majus

Lymphomas arising in the female genital tract are extremely uncommon. Diffuse large B-cell lymphoma and follicular lymphoma are the most common types. We describe the case of an 80-year-old woman with a recurrent lesion in the vulva initially diagnosed as a lymphoma-like lesion and evolving 7 years later into a marginal zone B-cell lymphoma (lymphoplasmacytic lymphoma). Diagnosis was based on the monotypic pattern of the plasmacellular component and the clonal rearrangement of immunoglobulin heavy chain genes. No previous cases of vulvar marginal zone B-cell lymphoma arising in the context of a persistent lymphoma-like lesion have been reported. We highlight the importance of differentiating benign from malignant lymphoid infiltrates in the vulva.

Evaluation of Antibiotic Therapy for Eradication of “ Candidatus Helicobacter heilmannii”

Triple-agent therapy with lansoprazole (15 mg/kg)-clarithromycin (50 mg/kg)-amoxicillin (50 mg/kg) twice daily for 7 days fully cleared "Candidatus Helicobacter heilmannii" from infected mouse stomachs. Moreover, gastric mucosa-associated lymphoid tissue lymphoma-like lesions in the stomach nearly disappeared in the treated mice 4 months after the therapy.

Distinction between lymphoma-like lesions and lymphoma of uterine cervix: a clinicopathologic study of 26 cases

To study the clinicopathologic features and differential diagnosis of lymphoma-like lesions and lymphoma of uterine cervix. Clinical data and hematoxylin and eosin-stained slides of 10 cases of lymphoma-like lesion and 16 cases of lymphoma of uterine cervix were reviewed. Immunohistochemical study for B- and T-cell markers and light chains (kappa, lambda) were performed on paraffin sections. The rearrangement status of immunoglobulin heavy chain (IgH) gene was analyzed with semi-nested polymerase chain reaction in 4 cases lymphoma-like lesion and 4 cases of lymphoma of uterine cervix. The age of patients with lymphoma-like lesion ranged from 24 to 54 years (medium = 43 years). The lesion generally presented with cervical erosion or polyp. Microscopically, it is characterized by focal or diffuse superficial infiltration of immunoblast-like large B cells intermingled with a polymorphic population of inflammatory cells, including plasma cells, eosinophils and neutrophils. Maturation of the transformed large B cells was also noticed. On the other hand, the age of the patients with lymphoma of uterine cervix varied from 28 to 78 years (medium = 58 years). Cervical mass or diffuse enlargement of cervix were the commonest clinical findings. The cases included 12 examples of diffuse large B-cell lymphoma and 4 examples of follicular lymphoma. The former was characterized by a diffuse monomorphic population of large atypical lymphoid cells, while neoplastic follicles were identified in the latter. Neither polymorphic inflammatory infiltrates nor maturation phenomenon was found. The immunostaining for kappa and lambda light chains was inconclusive. Molecular study showed clonal rearrangement of IgH gene in all cases of cervical lymphoma, as well as 2 cases of lymphoma-like lesion. The distinction between lymphoma-like lesion and lymphoma of uterine cervix depends primarily on the clinical and histopathologic features. Assay for rearrangement of IgH gene may be helpful in differential diagnosis, though monoclonality can be detected in some benign lesions as well.

Lymphoma-like Lesion of the Uterine Cervix

Lymphoma-like lesion of the female genital tract is rare. We report 12 cases of lymphoma-like lesions of the cervix in patients ranging from 27-54 years of age (mean 41). The commonest clinical presentation was post-coital bleeding (8), which was followed by vaginal bleeding (2) and leukorrhagia (4). Grossly, the lesions were either polypoid (8) or ulcerated (4). On histological examination, the lesions were eroded and involved the superficial mucosa 2-12 mm (mean 4 mm) in depth. They comprised sheets of dense populations of predominantly large lymphoid cells admixed with small lymphocytes, plasma cells, and neutrophils. Follicle formation was occasionally seen. Immunostaining revealed the majority of the large cells were B cells (CD20(+), CD79a(+)) with no aberrant CD5 and CD43 expression. The lymphoid cells in the follicle were CD10(+) and bcl6(+) but negative for bcl-2. Cyclin D1 was negative. There was no immunoglobulin light chain restriction and polymerase chain reaction for T cell receptor-gamma chain gene and immunoglobulin heavy chain gene demonstrated polyclonal patterns. In situ hybridization for EBER and high risk HPV 6/11 and 16/18 were negative. All patients were well with one case developing local recurrence in the follow-up period up to 7 years.

Lymphoma-like lesion of uterine cervix

1.病例简介:患者女,40岁.发现阴道突出物6 d,于2003年6月18日就诊.患者自述阴道突出物平卧后消失,偶有接触性出血.妇科检查于宫颈见一息肉状新生物,未见明显肿块,宫旁未见特殊.临床诊断:宫颈新生物,性质待查。

Oral effects of low-dose methotrexate treatment

Methotrexate is used increasingly in low-dose regimes for a variety of conditions, particularly rheumatoid arthritis. While certain adverse effects of low-dose methotrexate have been described in detail, oral complications have received little attention. This article includes a summary of the uses and pharmacology of low-dose methotrexate and the mechanisms that lead to general and oral toxicity. The literature relevant to potential oral adverse effects is discussed and 7 illustrative cases are presented. The oral effects noted range from nonhealing ulcers to lymphoma-like lesions. Dental practitioners should be aware of the possible oral effects of low-dose methotrexate that have so far been largely unrecognized.

Immunogenetic analysis of gastric MALT lymphoma-like lesions induced by Helicobacter pylori infection in neonatally thymectomized mice

Most gastric mucosa-associated lymphoid tissue (MALT) lymphomas are caused by Helicobacter pylori (H. pylori) infection. We previously reported that acquired lymphoid follicles with germinal centers were induced by H. pylori infection in neonatally thymectomized (nTx) mice. In the present study, we developed gastric MALT lymphoma-like lesions in nTx mice by long-term H. pylori infection, and performed immunogenetic analyses. BALB/c mice were thymectomized on the 3rd day after birth. At 6 weeks of age, mice were orally infected with 108H. pylori and serially killed 2, 4, 6, and 12 months later. Normal BALB/c and noninfected nTx mice served as controls. Follicle formation occurred after 2 months of H. pylori infection in the nTx mice. Follicle formation and infiltration of intraepithelial lymphocytes progressed in a time-dependent manner. Lymphoepithelial lesions, a characteristic feature of MALT lymphoma, also occurred in a time-dependent manner (100% at 12 months). Serum immunoelectrophoresis revealed a monoclonal band (M-protein) in 30% (3/10) of mice 6 months after infection. M-protein-positive mice had amplification of one or two IgM and/or IgG heavy-chain genes in the gastric B lymphocytes, as determined with polymerase chain reaction, suggesting mono- or oligoclonality. Overexpression of Bcl-XL protein was immunohistologically observed in the infiltrating B lymphocytes and in some follicular B lymphocytes in 80% (8/10) of the cases at 12 months. Thus, H. pylori infection is involved in the development of gastric MALT lymphoma-like lesions in nTx mice. Our mouse model is useful for clarifying the pathogenetic mechanism of gastric MALT lymphoma by H. pylori infection.

Is posttransplant lymphoproliferative disorder (PTLD) caused by any specific immunosuppressive drug or by the transplantation per se?

An association between posttransplant lymphoproliferative disorder (PTLD) and cyclosporine A (CsA) and OKT3 has often been postulated on the basis of retrospective studies, although a randomized study with PTLD as the endpoint will probably never be performed. Because focus on PTLD coincided with the use of these drugs, a bias could be suspected. In a retrospective, nonrandomized study, we reevaluated all lymphoma-like lesions arising in kidney-transplant patients grafted at our center during 1969 to 1998 and observed up to 2002. Case pathology was reviewed, and an association with Epstein-Barr virus (EBV) infection (and latency pattern) was assessed. We did not find any significant difference in the incidence of PTLDs when comparing the prednisolone/azathioprine, and CsA eras (P=0.89), the periods before or after OKT3 (P=0.61), and those before or after antilymphocyte globulin (ALG) (P=0.22). Occurrence time was shorter in the CsA (P=0.059), OKT3 (P=0.007), and ALG (P=0.007) eras. In the OKT3 era, 182 patients received, and 224 did not receive, OKT3; after the same observation time, there had been eight and five PTLDs, respectively (P=0.34). The use of mycophenolate mofetil (MMF) was associated with a reduction in the number of PTLDs (P=0.01). EBV was detected in 16 of 21 (76%) cases. We found no evidence to implicate any one drug regime preferentially in the development of PTLDs. The risk of developing PTLD seems to be a result of the whole transplantation process, which includes the antigenicity of the foreign graft, the immunosuppression resulting in inadequate cytotoxic T-cell activity, and the result of EBV infection. An important minority of cases are EBV negative.