Genetic subtype classification using a simplified algorithm and mutational characteristics of diffuse large B-cell lymphoma in a Japanese cohort.

Recent large-scale genetic studies have proposed a new genetic classification of diffuse large B-cell lymphoma (DLBCL), which is clinically and biologically heterogeneous. However, the classification methods were complicated to be introduced into clinical practice. Here we retrospectively evaluated the mutational status and copy number changes of 144 genes in 177 Japanese patients with DLBCL, using targeted DNA sequencing. We developed a simplified algorithm for classifying four genetic subtypes-MYD88, NOTCH2, BCL2, and SGK1-by assessing alterations in 18 representative genes and BCL2 and BCL6 rearrangement status, integrating the significant genes from previous studies. In our cohort and another validation cohort from published data, the classification results in our algorithm showed close agreement with the other established algorithm. A differential prognosis among the four groups was observed. The NOTCH2 group showed a particularly poorer outcome than similar groups in previous reports. Furthermore, our study revealed unreported genetic features in the DLBCL subtypes that are mainly reported in Japanese patients, such as CD5-positive DLBCL and methotrexate-associated lymphoproliferative disorders. These results indicate the utility of our simplified method for DLBCL genetic subtype classification, which can facilitate the optimisation of treatment strategies. In addition, our study highlights the genetic features of Japanese patients with DLBCL.

Outcomes of methotrexate-associated lymphoproliferative disorders in rheumatoid arthritis patients treated with disease-modifying anti-rheumatic drugs.

Recently, the use of targeted synthetic or biological disease-modifying anti-rheumatic drugs (ts/bDMARDs) in addition to conventional synthetic (cs)DMARDs including methotrexate (MTX) for rheumatoid arthritis (RA) has increased. However, whether ts/bDMARDs are associated with the development and clinicopathological features of MTX-associated lymphoproliferative disorder (MTX-LPD) in patients with RA remains unknown. Therefore, we evaluated the clinical outcomes of 121 patients with MTX-LPD. Results showed that prior use of ts/bDMARDs was not associated with the different histopathological subtypes of MTX-LPD. Patients with polymorphic-type LPD had a better event-free survival than those with diffuse large B-cell lymphoma (DLBCL), classical Hodgkin lymphoma and peripheral T-cell lymphoma. The pathological subtype of lymphoma could predict the clinical outcome of MTX-LPD. In patients with DLBCL, the use of tumour necrosis factor-alpha (TNF-α) inhibitors prior to MTX-LPD onset was associated with a higher non-relapse mortality. Further, patients with RA previously treated with Janus kinase (JAK) inhibitors more commonly required chemotherapy than those treated with csDMARDs alone, indicating disease aggressiveness. Hence, special caution should be observed when managing patients with MTX-LPD previously treated with JAK or TNF-α inhibitors for RA.

[Oral Mucosal Diffuse Large B-cell Lymphoma Caused by Long-term Oral Methotrexate:Report of One Case].

A case of primary oral mucosal diffuse large B-cell lymphoma(DLBCL)due to long-term use of methotrexate(MTX)for the treatment of rheumatoid arthritis(RA)was admitted to the Department of Hematology,Fujian Medical University Union Hospital.We analyzed and discussed the clinical features,diagnosis and treatment,and prognosis of specific malignant lymphoma induced by MTX in this RA patient.Our purpose is to improve the awareness and knowledge of other iatrogenic immunodeficiency-associated lymphoproliferative disorders of clinicians and pathologists.This study provides a new reference for the clinical diagnosis and treatment of MTX-associated DLBCL.

Methotrexate-associated lymphoproliferative disorder in the stomach and duodenum: a case report.

BACKGROUND: Methotrexate-associated lymphoproliferative disorder (MTX-LPD) can present as a benign lymphoid proliferation or a malignant lymphoma in patients taking MTX. Almost 50% of MTX-LPD cases show spontaneous remission after withdrawal of MTX treatment. Studies have suggested that the hyper-immune state of rheumatoid arthritis, the immunosuppressive state associated with MTX, and the carcinogenicity of the Epstein-Barr virus might contribute to MTX-LPD development. Although most cases of MTX-LPD occur at extranodal sites, few cases of MTX-LPD affecting the stomach and duodenum have been reported. To our knowledge, no other study has reported on the endoscopic observations of dramatic withdrawal and appearance of multiple digestive tract lesions in a short period of time. Herein, we report the clinical course and imaging findings of our case, which may be useful for understanding the pathological condition of MTX-LPD. CASE PRESENTATION: We describe the case of a 70-year-old woman with MTX-LPD of the stomach and duodenum. Disease regression was temporarily achieved after cessation of MTX treatment; however, it subsequently recurred, and complete response was only achieved after six cycles of rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisolone (R-CHOP) chemotherapy. CONCLUSIONS: The first-choice therapy for patients taking MTX who develop suspected MTX-LPD should be the withdrawal of MTX treatment. Even after remission is achieved, patients should be kept under careful observation, and if the disease recurs, chemotherapy should be commenced promptly.

Clinicopathological analysis of methotrexate-associated lymphoproliferative disorders: Comparison of diffuse large B-cell lymphoma and classical Hodgkin lymphoma types.

Patients with rheumatoid arthritis often develop methotrexate-associated lymphoproliferative disorders (MTX-LPD) during MTX treatment. MTX-LPD occasionally regresses spontaneously after simply discontinuing MTX treatment. In patients without spontaneous regression, additional chemotherapy is required to avoid disease progression. However, the differences between spontaneous and non-spontaneous regression have yet to be elucidated. To clarify the factors important for spontaneous regression, we analyzed the clinicopathological features of 51 patients with rheumatoid arthritis who developed MTX-LPD (diffuse large B-cell lymphoma [DLBCL]-type [n = 34] and classical Hodgkin lymphoma [CHL]-type [n = 17]). We examined the interval from MTX discontinuation to the administration of additional chemotherapy. The majority of DLBCL-type MTX-LPD patients (81%) exhibited remission with MTX discontinuation alone. In contrast, the majority of CHL-type MTX-LPD patients (76%) required additional chemotherapy. This difference was statistically significant (P = 0.001). However, overall survival was not significantly different between DLBCL-type and CHL-type (91% vs 94%, respectively; P > 0.05). Thus, the morphological differences in the pathological findings of MTX-LPD may be a factor for spontaneous or non-spontaneous regression after discontinuation of MTX.

Hepatosplenic Hodgkin lymphoma without lymphadenopathy following reversible methotrexate-associated lymphoproliferative disorder.

Lymphoproliferative disorders (LPDs) occur more frequently in rheumatoid arthritis (RA) patients treated with immunosuppressive agents than in the non-RA population. However, the various forms of disease progression have not yet been elucidated in detail. We encountered a case of Epstein-Barr virus (EBV)-positive atypical polymorphous LPD in the cervical and intraabdominal lymph nodes with hepatosplenomegaly in an 88-year-old female with RA who had taken infliximab and methotrexate (MTX) for six years. Although spontaneous remission occurred following the withdrawal of infliximab and MTX, reversible LPD evolved into hepatosplenic Hodgkin lymphoma without lymphadenopathy presenting as a cholestatic febrile illness. Our findings suggest that the recurrent lesions of MTX-associated LPDs may not always coincide with the primary lesion and may present unexplained findings based on various extranodal diseases.

Prognostic factors of methotrexate-associated lymphoproliferative disorders associated with rheumatoid arthritis and plausible application of biological agents.

OBJECTIVES: To determine prognostic factors of methotrexate-associated lymphoproliferative disorder (MTX-LPD) and evaluate the efficacy and safety of biological therapy in rheumatoid arthritis (RA) complicated with MTX-LPD. METHODS: Thirty RA patients who developed MTX-LPD were investigated in this study. We compared the clinical and laboratory parameters of patients who achieved regression of LPD by MTX withdrawal with those who required chemotherapy and evaluated the clinical course of RA after LPD development. RESULTS: Twenty-three patients (76.7%) achieved regression of LPD by MTX withdrawal. Chemotherapy-free patients had a tendency of shorter RA duration (13.1 vs. 22.0 years, p = 0.108) and higher doses of MTX at LPD diagnosis (8.0 vs. 5.3 mg/w, p = 0.067) than patients who required chemotherapy. A significantly higher positive rate of peripheral blood Epstein-Barr virus (EBV)-DNA was observed in the chemotherapy-free group (9/9 vs. 0/3, p = 0.0002). Of 15 patients that received biological agents after LPD development, 14 patients (93.3%) demonstrated an improved disease activity of RA and persistent remission of LPD, whereas only one patient experienced relapse of LPD during tocilizumab therapy. CONCLUSIONS: Peripheral blood EBV-DNA positivity is a potential prognostic marker of better outcome in MTX-LPD. Biological agents could be an option for the treatment of RA patients with MTX-LPD.

Analysis of Notch1 protein expression in methotrexate-associated lymphoproliferative disorders.

Methotrexate (MTX)-associated lymphoproliferative disorder (MTX-LPD) is a lymphoproliferative disorder in patients treated with MTX. The mechanism of pathogenesis is still elusive, but it is thought to be a complex interplay of factors, such as underlying autoimmune disease activity, MTX use, Epstein-Barr virus infection, and aging. The NOTCH genes encode receptors for a signaling pathway that regulates various fundamental cellular processes, such as proliferation and differentiation during embryonic development. Mutations of NOTCH1 have been reported in B-cell tumors, including chronic lymphocytic leukemia/lymphoma, mantle cell lymphoma, and diffuse large B-cell lymphoma (DLBCL). Recently, it has also been reported that NOTCH1 mutations are found in post-transplant lymphoproliferative disorders, and in CD20-positive cells in angioimmunoblastic T-cell lymphoma, which might be associated with lymphomagenesis in immunodeficiency. In this study, to investigate the association of NOTCH1 in the pathogenesis of MTX-LPD, we evaluated protein expression of Notch1 in nuclei immunohistochemically in MTX-LPD cases [histologically DLBCL-type (n = 24) and classical Hodgkin lymphoma (CHL)-type (n = 24)] and de novo lymphoma cases [DLBCL (n = 19) and CHL (n = 15)]. The results showed that among MTX-LPD cases, the expression of Notch1 protein was significantly higher in the DLBCL type than in the CHL type (P < 0.001). In addition, among DLBCL morphology cases, expression of Notch1 tended to be higher in MTX-LPD than in the de novo group; however this difference was not significant (P = 0.0605). The results showed that NOTCH1 may be involved in the proliferation and tumorigenesis of B cells under the use of MTX. Further research, including genetic studies, is necessary.

Diagnostic utility of cytology in a patient with Epstein-Barr virus-positive mucocutaneous ulcer in palatine tonsils: A case report.

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a newly established immunodeficiency-related disease. Herein, we report a case of EBVMCU and focus on its cytological usefulness for diagnosis. An 82-year-old man manifested pharyngalgia, dysphagia, and oral pain. His medical history included rheumatoid arthritis that had been treated with methotrexate. Clinically, peritonsillar abscess was suspected, but since neoplastic lesions, including malignant lymphoma (ML), could not be excluded, a series of cytohistological examination was attempted. Despite some alarming findings (e.g., frequent mitoses), fine-needle aspiration and touch imprint cytology consistently revealed a heterogeneous population of lymphoid and plasmacytoid cells with mild nuclear atypia. The final diagnosis of EBVMCU was established based on the permanent histologic specimen; however, retrospectively, cytology was more representative of the benign nature of the lesion than histology, helping a great deal to differentiate it from ML. Cytology can be a useful tool for the correct diagnosis of EBVMCU.

Primary Hepatic Other Iatrogenic Immunodeficiency-Associated Lymphoproliferative Disorders After Methotrexate Therapy.

Prior reports described cases of lymphoproliferative diseases occurring after methotrexate (MTX) administration, which are called methotrexate-associated lymphoproliferative disorders (MTX-LPDs). It has become clear that these lymphoproliferative diseases also occur following treatment with other immunosuppressive drugs, and they have been termed as other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPDs). In most of these cases, the duration of immunosuppressive drugs is very long, on the order of years. In the present study, we evaluated the development of lymphoproliferative disease despite the short duration of immunosuppressive treatment and determined the tumor doubling time. A 71-year-old woman was diagnosed with adult-onset Still's disease. The patient was administered prednisone 30 mg per day starting on February 25, 2022 and MTX 6 mg per week starting 2 weeks later. Because she was a hepatitis B virus (HBV) carrier, nucleic acid analog therapy was also started to prevent HBV activation. Eight weeks later, biweekly tocilizumab was started. After 5 months of MTX administration, a solitary liver tumor measuring 37 × 32 mm2 was detected. Three months later, repeat computed tomography revealed that the liver tumor had grown rapidly to 7 cm in diameter. We considered the possibility of OIIA-LPDs and stopped MTX therapy. Biopsy specimens of the liver tumor exhibited lymphocyte proliferation, which was consistent with OIIA-LPDs. The doubling time for tumor growth was 33 days. Despite withdrawing MTX for 6 weeks, the tumor continued to grow, and thus, the patient was referred to the hematology unit. In previously reported cases of MTX-LPDs of hepatic origin, the average duration of MTX administration was 7.3 (2 - 13) years. This report describes a primary hepatic OIIA-LPDs-associated tumor that rapidly increased in size after an extremely short period of MTX administration.

Hepatic and lung methotrexate-associated polymorphic lymphoproliferative disorders arising during postoperative follow-up of renal cell carcinoma: a case report.

INTRODUCTION: Methotrexate induces lymphoproliferative disorders on rare occasions; however, its pathogenesis remains unknown. A clinical diagnosis based on imaging studies alone is often difficult. CASE PRESENTATION: A 57-year-old Japanese woman was referred to our department for the evaluation of multiple lung and hepatic nodules that developed during methotrexate treatment for rheumatoid arthritis. Since she had a history of nephrectomy for localized renal cell carcinoma, multiple lung and hepatic metastases were initially considered. However, pathological diagnosis of the lung nodules (needle biopsy) revealed methotrexate-associated polymorphic-type lymphoproliferative disorders. After methotrexate discontinuation, continuous smooth shrinkage of the lung and liver lymphoproliferative disorders was observed. CONCLUSION: Methotrexate-associated lymphoproliferative disorders should be considered in the event of newly appearing neoplastic lesions, even during follow-up for renal cell carcinoma, if methotrexate is being administered.

Methotrexate-Associated Lymphoproliferative Disorders Mimicking Granulomatosis With Polyangiitis: A Radiological Diagnostic Challenge.

Methotrexate-associated lymphoproliferative disorders (MTX-LPD) frequently involve the extranodal organs throughout the body. Among the extranodal occurrences of MTX-LPD, pulmonary involvement is most frequent. In contrast, there are only a few reports of MTX-LPD in the nasal cavity or paranasal sinuses. Moreover, there are no previous reports of MTX-LPD mimicking granulomatosis with polyangiitis (GPA) in imaging examinations. We describe a case of a 53-year-old woman with MTX-LPD mimicking GPA in the nasal cavity and lungs. She complained of left nasal obstruction and discharge, general fatigue, and continual fever for 2 months. The patient had been diagnosed with rheumatoid arthritis and received methotrexate (MTX) for over 10 years. Contrast-enhanced computed tomography revealed unenhanced masses in the nasal cavity and multiple masses with cavitary changes in the bilateral lungs, suggesting GPA. However, histological examination of the nasal lesion and a history of MTX treatment indicated a diffuse large B-cell lymphoma type MTX-LPD. Two weeks after MTX withdrawal, prominent improvements in both lesions were observed. Complete regression of the nasal lesion was observed 3 months after discontinuation of MTX. Thus, MTX-LPD may mimic GPA in imaging examinations.

Spontaneous regression of breast lymphoproliferative disorders after withdrawal of methotrexate in rheumatoid arthritis patients with Epstein-Barr virus infection: a case report and review of the literature.

BACKGROUND: Lymphoproliferative disorder (LPD) has been shown to occur after treatment with methotrexate (MTX). Currently, MTX-LPD has become widely recognized, but its mechanism and prognostic factors remain unclear. CASE PRESENTATION: We report the first case of Epstein-Barr virus (EBV)-associated MTX-LPD of the breast. A 63-year-old Asian woman with long-term rheumatoid arthritis presented to our facility with intermittent fever. A physical examination revealed a 3-cm lump in her left breast. She had been taking MTX for the past 15 years. Laboratory studies revealed slightly elevated levels of EBV-viral capsid antigen antibody immunoglobulin G and EBV nuclear antibody. Contrast-enhanced computer tomography revealed a mass in the left breast, a subcutaneous nodule in the abdomen, a mass in the left lung, and a nodule in the left retroperitoneum. The definitive diagnosis was consistent with MTX-LPD merging into an EBV-positive, diffuse large B-cell lymphoma. Six months following the withdrawal of MTX, the breast mass had markedly shrunk and the patient remained in good health for 1 year with no evidence of relapse of LPD. CONCLUSION: MTX-LPD rarely occurs in the breast, and it is difficult to diagnose because there have only been six reported cases of breast MTX-LPD reported in the literature. EBV-positive MTX-LPD tends to regress spontaneously after MTX withdrawal, and our case also had similar results. It is important to make an appropriate diagnosis of MTX-LPD of the breast based on imaging and pathology to determine the appropriate treatment protocol for this rare disorder.

A case of resected pulmonary lymphomatoid granulomatosis.

Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus-associated B-cell lymphoproliferative disorder and was incorporated into the WHO classification of Tumours of the Lung, Pleura, Thymus and Heart in 2015. LYG is known to be associated with the host's immune function, and can be caused by some immunosuppressive agents, including methotrexate. A woman in her sixties with an 18-year history of methotrexate treatment for rheumatoid arthritis visited our hospital after detection of an abnormal chest shadow on her radiograph. She had been having anemia and a slight fever. Computed tomography (CT) revealed a 2.9-cm sized nodule in her left lung and hilar adenopathy, which suggested a primary lung carcinoma or an inflammatory lesion. We performed a left upper lobectomy with lymph node dissection for the purpose of diagnosis and treatment. Pathologic findings revealed that the tumor was a grade 3 LYG based on the number of EBV-positive B cells. The patient was treated with two chemotherapy regimens including R-CHOP at another hospital, and survived for four years after resection without recurrence in the lung. It is rare to find a case resected LYG, and the clinical or pathological findings of our case are expected to be extremely helpful in studying this disease and improving the understanding of this disease.

Primary Central Nervous System T-cell Lymphoma as Methotrexate-associated Lymphoproliferative Disorders: Case Report.

We report a rare case of primary central nervous system (CNS) lymphoma as methotrexate-associated lymphoproliferative disorders (MTX-LPD). A 75-year-old woman who had been treated for rheumatoid arthritis (RA) with MTX for 3 years was admitted to our hospital complaining of unsteady gait, nausea, and vomiting. T2-weighted image of magnetic resonance imaging (MRI) showed multiple high intensity mass-like lesions including right lateral, frontal and temporal lobes, and right cerebellar hemisphere. We performed surgical biopsy, and the pathological and immunohistochemical examinations identified T-cell lymphoma. The tumor regressed and the symptoms were resolved soon after MTX withdrawal. Primary CNS lymphoma due to MTX-LPD is a rare disease and only eight cases including ours are reported.

Intraoral localized methotrexate-associated lymphoproliferative disorders concurrent with antiresorptive agent-related osteonecrosis of the jaw: A case report and literature review.

Intraoral localized methotrexate-associated lymphoproliferative disorders can cause antiresorptive agent-related osteonecrosis of the jaw associated with infection due to its immunological abnormalities and ulcer formation.

The potential usefulness of sputum cytology in the conclusive diagnosis of methotrexate-associated lymphoproliferative disorders: A case report.

BACKGROUND: Methotrexate has been used as an anchor drug for the treatment of rheumatoid arthritis and is considered to be a cause of methotrexate-associated lymphoproliferative disorder. Spontaneous regression can occur after withdrawal of methotrexate and may be associated with Epstein-Barr virus positivity and non-diffuse large B cell lymphoma histological type. Methotrexate-associated lymphoproliferative disorders are often diagnosed pathologically by lung biopsy. To the best of our knowledge, there have been no studies on the cytological diagnosis of methotrexate-associated lymphoproliferative disorder using sputum smears. CASE: A 70-year-old man, who was diagnosed with rheumatoid arthritis 13 years previously and who had been treated with methotrexate, presented shortness of breath and productive cough. Methotrexate-associated lymphoproliferative disorder was suspected as the sputum cytology showed many atypical lymphoid cells with hyperchromatic enlarged nuclei, foamy cytoplasm and distinct nucleoli. Chest computed tomography revealed multiple nodular shadows with interstitial pneumonia in the bilateral lower lung field. A lung biopsy specimen contained atypical lymphoid cells that were immunohistochemically positive for CD20 and MUM-1, and weakly positive for bcl-6, but negative for CD3 and CD10. There were no Epstein-Barr virus-infectious lymphoid cells by ISH-EBER. He was finally diagnosed with methotrexate-associated lymphoproliferative disorder (non-germinal center B-cell-like diffuse large B cell lymphoma histological type). Most of the nodules disappeared spontaneously following the withdrawal of methotrexate. DISCUSSION AND CONCLUSION: A cytologically conclusive diagnosis of methotrexate-associated lymphoproliferative disorder may be reached using sputum smears and clinical information.

Hepatic methotrexate-associated lymphoproliferative disorders identified by multiple liver tumors: a case report and review of the literature.

BACKGROUND: Methotrexate, an immunosuppressant, is widely used as the standard therapeutic drug for rheumatoid arthritis. With the increasing frequency of use of methotrexate, adverse effects of methotrexate have been reported, one of which is known as methotrexate-associated lymphoproliferative disorders. The etiology of hepatic methotrexate-associated lymphoproliferative disorders remains largely unknown. To date, there have only been ten cases of hepatic methotrexate-associated lymphoproliferative disorders reported in the English literature and a case report is very rare. CASE PRESENTATION: An 82-year-old Japanese man with rheumatoid arthritis treated with methotrexate presented with fever. Contrast-enhanced computed tomography showed multiple hypovascular nodules in his liver, spleen, and lung, and para-aortic lesions. Endoscopic ultrasound-guided fine-needle aspiration biopsy for liver tumors was performed, and pathological results identified cluster of differentiation 20-positive lymphocytes. Discontinuance of methotrexate led to regression of the nodules and a final definitive diagnosis of methotrexate-associated lymphoproliferative disorders was made. CONCLUSIONS: We review 11 reported cases of hepatic methotrexate-associated lymphoproliferative disorders including the present case. Physicians should discontinue methotrexate in patients with rheumatoid arthritis treated with methotrexate when elevated soluble interleukin-2 receptor and hypovascular lesions in contrast-enhanced computed tomography are confirmed considering the possibility of methotrexate-associated lymphoproliferative disorders.

Highly aggressive plasmablastic neoplasms in patients with rheumatoid arthritis treated with methotrexate.

Patients with rheumatoid arthritis occasionally develop lymphoproliferative disorders. Methotrexate-associated lymphoproliferative disorders is a lymphoproliferative disease or lymphoma in patients treated with methotrexate for autoimmune diseases, such as rheumatoid arthritis. Here we report two rare cases of highly aggressive plasmablastic lymphoproliferative disorders in rheumatoid arthritis treated with methotrexate. Case 1 is a 68-year-old female patient with leukemic transformation of malignant lymphoma. She received methotrexate therapy for rheumatoid arthritis for >6 years. The patient showed rapid progressive course and died on the 2nd hospital day. After the death, we diagnosed the patient as plasmablastic lymphoma. Case 2 is an 80-year-old female patient with plasmablastic plasma cell myeloma, with a history of methotrexate treatment for rheumatoid arthritis for >5 years. Although M-protein was decreased by chemotherapy, bone marrow examination revealed the further increase of plasmablastic cells and she died 2 months later. The present cases were difficult to diagnose because proliferation of malignant plasmablasts was hardly predicted because neither lymph node enlargement nor an evident M-protein was observed. Both cases showed aggressive features and extremely poor prognosis. Clinicians should be aware of the underlying malignant plasmablastic proliferation when inexplicable inflammatory findings are observed in inactive rheumatoid arthritis patients.

Methotrexate-associated Classical Hodgkin Lymphoma Shows Distinct Clinicopathological Features but Comparable Clinical Outcomes With Sporadic Cases.

BACKGROUND/AIM: Methotrexate (MTX)-associated classical Hodgkin lymphoma (CHL) is a rare disease, and its prognosis remains unclear. MATERIALS AND METHODS: Our study retrospectively compared clinicopathological features and clinical outcomes of patients with MTX-CHL (n=6) and sporadic CHL (n=40). RESULTS: MTX-CHL was more frequently the mixed cellularity subtype and positive for Epstein-Barr virus, but less frequently positive for CD20 than sporadic CHL. Clinically, MTX-CHL was more frequent in advanced stage than sporadic CHL and often associated with extranodal disease. After the cessation of MTX, transient spontaneous regression was observed in two MTX-CHL cases. Eventually, all patients with MTX-CHL required chemotherapy, which gave similar complete remission rates at 2 years compared to sporadic CHL. Patients with MTX-CHL tended to have a higher incidence of grade 3 or more neutropenia. CONCLUSION: The present study revealed differences in clinicopathological features but similarities in clinical outcomes of MTX-CHL and sporadic CHL.