Primary Mediastinal Research Articles

The management of primary mediastinal B-cell lymphoma: a British Society for Haematology Good Practice Paper.

This Good Practice Paper was compiled according to the British Society for Haematology (BSH) process at http://www.b-s-h.org.uk/guidelines. The BSH produces Good Practice Papers to recommend good practice in areas where there is a limited evidence base but for which a degree of consensus or uniformity is likely to be beneficial to patient care. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) nomenclature was used to evaluate levels of evidence and to assess the strength of recommendations. The GRADE criteria can be found at http://www.gradeworkinggroup.org and is also detailed in Table 1.

Rearrangements of Immunoglobulin Genes in Tumor Cells of Patients with Primary Mediastinal (Thymic) Large B-Cell Lymphoma

Background. Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is a malignant tumor with large atypical lymphoid cells expressing post-germinal differentiation markers. Rearrangements of immunoglobulin genes in PMBCL are revealed in 30-65 % of cases. Immunoglobulin molecules, however, are expressed neither on the surface, nor in cytoplasm of tumor cells. Aim. To assess cell clonality rate on the basis of rearrangements of immunoglobulin heavy/light chain genes; to determine rearrangement stability at the time of relapse development; to study the range of rearrangements and clonal relationship with primary tumor in metachronous development of mediastinal gray zone lymphoma. Materials & Methods. The assessment of rearrangements of immunoglobulin heavy/light chain genes was based on molecular analysis of 29 primary tumor biopsies and 4 tissue samples with histologically and immunohistochemically verified relapses or metachronous lymphoma development. Results. In 16 (55.2 %) out of 29 cases a rearrangement of immunoglobulin heavy chain genes was reported, in 7 (24.1 %) cases a rearrangement of light chain genes was identified, in 6 (20.7 %) cases no rearrangements of immunoglobulin heavy/light chain genes were found. On the basis of immunoglobulin gene analysis in 2 patients with early relapse a tumor clone was detected that was identical with the one identified at the onset of the disease. In 2 patients with complete remission a metachronous development of mediastinal gray zone lymphoma was reported, whereas molecular genetic analysis revealed a change/disappearance of initial clonal rearrangements of immunoglobulin genes. Conclusion. Total detection rate of B-cell clonality in PMB-CL was 79.3 %. Molecular genetic analysis confirmed that initial clonal rearrangements of immunoglobulin genes were preserved in early relapses, and invalidated tumor clonal relationship in a metachronous development of mediastinal gray zone lymphoma.

Pathological Study of Primary Mediastinal Lesions in a Tertiary Care Hospital

Pathological Study of Primary Mediastinal Lesions in a Tertiary Care Hospital

Primary Mediastinal (Thymic) Large B-Cell Lymphoma: Experience in Treating 131 Patients at a National Medical Research Center in Russia

Background. Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is one of the primary extranodal tumors and originates from B-cells of thymic medulla. This disease is characterized by specific immunomorphologic and genetic features which distinguish it from other malignant lymphoproliferative disorders with similar parameters. Standard PMBCL treatment consists of immunochemotherapy and subsequent radiotherapy of residual mediastinal tumor. The advantages of one immunochemotherapy regimens over the other in controlled studies have not been shown. Aim. To study current approaches to chemoradiation in PMBCL patients with an attempt to individualize them focusing on various prognostic factors. Materials & Methods. The data of 131 patients with newly diagnosed PMBCL were analyzed, all of them were treated at NN Blokhin National Medical Cancer Research Center in the period from 2000 to 2017. More than a half were women (58 %), median age was 30 years (range 16-70). At different historical periods PMBCL treatment was performed using different immunochemotherapy regimens: MACOP-B±R in 55 (42 %) patients, R-CHOP in 40 (30.5 %) patients, and R-DA-EPOCH in 36 (27.5 %) patients. Radiotherapy was used to treat 99 out of 131 patients. Results. In general, the treatment of all PMBCL patients (n = 131) appeared to be highly effective. The remission rate was 87 %, 3-year progression-free survival (PFS) and overall survival (OS) was 78 % and 88 %, respectively. With median follow-up of 37 months relapses and progression of the disease were detected in 17 (13 %) out of 131 patients within a period of 13 months after initiation of antitumor treatment. There was not a single case of late relapse. The treatment of relapsed patients was not effective: 12-month OS was not higher than 37 %. Intensive immunochemotherapy regimens ACOP±R, R-DA-EPOCH) do not differ in their effectiveness, but they have significant advantages over the standard R-CHOP regimen. The results of positron emission tomography (PET) considered to be an important prognostic factor in PMBCL treatment: 3-year PFS in the PET-negative group was 92 % vs. 26 % in the PET-positive group. Conclusion. The optimal algorithm of PMBCL treatment was elaborated with consideration of clinical factors, immunochemotherapy programs, degrees of tumor regression, its metabolic activity, and radiotherapy method and irradiation area.

Nivolumab Combined with Brentuximab Vedotin for Relapsed/Refractory Primary Mediastinal Large B-Cell Lymphoma: Preliminary Results from the Phase 2 CheckMate 436 Trial

Nivolumab Combined with Brentuximab Vedotin for Relapsed/Refractory Primary Mediastinal Large B-Cell Lymphoma: Preliminary Results from the Phase 2 CheckMate 436 Trial

Allogeneic Stem Cell Transplantation Provides Durable Remission in Patients with Primary Mediastinal Large B-Cell Lymphoma

Allogeneic Stem Cell Transplantation Provides Durable Remission in Patients with Primary Mediastinal Large B-Cell Lymphoma

Bi-Institutional Report on Consolidative Proton Therapy after Initial Chemotherapy for Mediastinal Diffuse Large B-Cell and Primary Mediastinal Large B-Cell Lymphomas

Combined modality therapy with R-CHOP (rituximab, cyclophosphamide, vincristine, prednisone) and radiation is a standard treatment option for mediastinal aggressive non-Hodgkin lymphomas (MANHL), however very intense “radiation-free” chemotherapy is gaining in use, in part due to concern over radiation toxicity. We investigated early outcomes for patients receiving chemotherapy followed by consolidative proton therapy (PT) in these pts with mediastinal lymphoma, a group of patients that have been shown to derive dosimetric benefit from PT compared to photon-based techniques. From 2011-2017, 24 adult patients with MANHL (either primary mediastinal large B cell lymphomas or mediastinal diffuse large B cell lymphoma) enrolled on either institutional review board-approved outcomes tracking protocols or registry studies received consolidative PT after first-line chemotherapy with R-CHOP (16 pts) or R-CHP-brentuximab vedotin (8 pts) at two academic institutions. Six cycles were given in 22 pts, and 4 cycles in 2 pts. Patients with relapsed disease at the time of PT were excluded. The majority were male (58%) with a median age of 36 [range 22-72]. Stage distribution included 10 stage I, 9 stage II, 3 stage III, and 2 Stage IV with 42% with B symptoms and 33% with extranodal involvement. The majority (87.5%) had disease that measured at least 7.5 cm before chemotherapy, with a median maximum dimension of 12 cm [range 4-23 cm]. Involved-site radiotherapy target volumes were used for all patients. Pts received a median dose of 30.6 Gy(RBE) [range 30–39.6 Gy(RBE)]. Pencil beam scanning was used in 33%, deep inspiratory breath hold was used in 33%, and both were used in 12.5%. Follow-up time was defined as time from start of PT to event or last follow-up. The median follow-up was 28 months (range, 1.2–76 months). The majority (75%) of pts were in complete metabolic response before PT with Deauville Score (DS) of 1 or 2, however 21% had DS4, none of whom relapsed. Of the 24 pts, there was only 1 local failure that occurred 19 months after PT within the high dose region in a pt with DS1. One patient relapsed below the diaphragm at 20 months. The one pt who had DS5 after chemotherapy died 11 months after PT with relapse in the hilum (out of field) and infradiaphragmatic. Consolidative PT was given 3 months after chemotherapy in this patient. The median mean lung dose was 6.7 Gy(RBE) [range 2.3-16.8], median lung V5 was 30% [range 12-59], median lung V20 was 16% [range 4-40]. The median mean heart dose was 10.9 Gy(RBE) [range 0.01-16.9]. None had grade 2 or higher radiation pneumonitis. Consolidative involved site PT following standard chemotherapy in aggressive mediastinal B cell lymphomas results in excellent local control (96%) with minimal toxicity in this bi-institutional early report.

Primer Mediastinal Büyük B Hücreli Lenfoma Hastalarımızın Tedavi Sonuçlarının Geriye Dönük Değerlendirilmesi

Primer Mediastinal Büyük B Hücreli Lenfoma Hastalarımızın Tedavi Sonuçlarının Geriye Dönük Değerlendirilmesi

Outcomes of Relapsed and Refractory Primary Mediastinal (Thymic) Large B Cell Lymphoma Treated with Second-Line Therapy and Intent to Transplant

Primary mediastinal (thymic) large B cell lymphoma is a subtype of diffuse large B cell lymphoma with distinct clinical, molecular, and genetic features, many of which overlap with Hodgkin lymphoma. Increasingly, initial therapy for these patients has used dose-dense chemotherapy with or without radiation with excellent results. In patients with relapsed and primary refractory disease, outcomes of second-line therapy followed by consolidation with high-dose therapy and autologous stem cell transplantation remains largely undefined. We reviewed the outcomes of 60 transplant-eligible patients with relapsed or refractory primary mediastinal (thymic) large B cell lymphoma enrolled on sequential protocols with uniform second-line therapy with intent to consolidate with autologous stem cell transplant. The estimated 3-year overall and event-free survivals for all patients were 61% and 57%, respectively, and 68% and 65%, respectively, for patients proceeding to stem cell transplant. Multivariable analysis of risk factors before transplant revealed that an incomplete response to initial therapy, advanced Ann Arbor stage at disease progression, and failure to achieve a partial remission or better to second-line therapy to be independently associated with inferior event-free and overall survival. A risk score based on these variables was able to identify patients who are unlikely to respond to conventional second-line strategies. These results suggest that salvage chemoradiotherapy with intent of subsequent high-dose therapy and autologous stem cell transplant is successful in most patients with relapsed and refractory primary mediastinal (thymic) large B cell lymphoma. Alternative strategies are warranted for a significant subset of patients with high-risk disease who are unlikely to be cured with this strategy.

Treatment Approaches and Outcomes for Primary Mediastinal Sarcoma: Analysis of 976 Patients

Primary mediastinal sarcomas are rare and deadly. Our objective was to describe the clinicopathological features, treatment strategies, and overall survival outcomes for a contemporary cohort of patients diagnosed with primary mediastinal sarcoma in the United States. We queried the National Cancer Database for cases of mediastinal sarcoma diagnosed from 2004 to 2012. Five-year overall survival (OS) was examined using the Kaplan-Meier method. Differences in OS were assessed using log-rank analysis and Cox proportional hazards regression. The mean age of diagnosis was 53 years (range, 0 to 90) with a male predominance (59.2%). The most common histological subtype was hemangiosarcoma (27.1%). Fewer than half of patients underwent surgery (48.9%), and 19.7% of patients had no treatment. For all patients, OS was 14.8%. The best unadjusted OS was seen in patients treated with surgery and radiation (40.1%); untreated patients had the worst unadjusted OS (4.2%). Of those who underwent surgery (n= 477, 48.9%), OS was significantly better for those who achieved an R0 resection (30.1% versus 18.9%; p= 0.002). In multivariable analysis, surgery combined with radiation therapy was again associated with the best survival (HR, 0.24; 95% CI, 0.16 to 0.36). Other factors associated with improved OS included younger age, fewer comorbidities, and leiomyosarcoma histology. Worse OS was associated with poorly differentiated or undifferentiated grade, metastases, treatment in the New England region, and having Medicaid or no insurance. Sex and tumor size had no effect on OS. The 5-year OS for primary mediastinal sarcoma is poor. Surgical resection can be successful and should be considered whenever possible.

Issue Highlights-May 2018 (94B3).

Issue Highlights-May 2018 (94B3).

Primary Mediastinal (Thymic) Large B-Cell Lymphoma: Diagnostics of Extramediastinal Lesions and Treatment Opportunities

Background. Current diagnostic methods and the introduction of molecular investigations into clinical practice allow to improve the understanding of classical primary mediastinal (thymic) large B-cell lymphoma (PMBCL). Aim. To investigate clinical characteristics of PMBCL patients with extramediastinal lesions. Materials & Methods. The study was performed from 2007 to 2017 in the National Medical Hematology Research Center and included 157 PMBCL patients. The data of 16 (10.2 %; 4 men and 12 women) patients with extramediastinal lesions were analyzed; the median age was 27 years (range 23-69). Results. The extramediastinal lesions were found in pancreas (6; 37.5 %), kidneys (5; 31.2 %), ovaries (3; 18.7 %), liver (3; 18.7 %), bone marrow (3; 18.7 %), and breasts (2; 12 %); the lesions in stomach, bones, soft tissues, spleen, adrenals, and small pelvis were observed each in a single case. In 15 of 16 cases extramediastinal lesions were accompanied by involvement of superior mediastinum, and only 1 patient had an isolated lesion in thoracic soft tissues without mediastinal involvement. The samples of 8 out of 16 patients were analyzed using PCR. In all samples overexpression of 2 or more genes (JAK2, TRAF1, MAL, PDL1, PDL2) was determined which allowed to confirm, and in some cases to revise the diagnosis of PMBCL. Overall 5-year survival (93 %) of patients with classical PMBCL with thoracic involvement was similar to the cohort with extramediastinal lesions. All unfavourable events (progression/ relapse) were identified at an early stage, i.e. within a year after the completion of therapy. Conclusion. PMBCL patients can have not only superior mediastinum involvement, but extramediastinal lesions as well, including bone marrow. The spreading of the disease beyond superior mediastinum should be differentiated from diffuse large B-cell lymphoma using standard evaluation methods, and molecular analysis in some cases.

Bone Marrow Involvement in Primary Mediastinal B-Cell Large-Cell Lymphoma

Abstract Introduction: Primary Mediastinal Large B-cell Lymphoma (PMBCL) is one of the primary extranodal lymphomas and originating from the thymic medulla B-cells. PMBCL is localized in the anterior and upper mediastinum, often with compression of the superior vena cava and with tumor infiltration of the pericardium, lungs, pleura. Sometimes there is impairment of the kidneys, adrenals, liver and central nervous system. Usually the bone marrow is not including. According to the WHO Classification 2008, if bone marrow is infiltrated by large B-cell lymphoma with mediastinal tumor mass, differential diagnosis between diffuse large B-cell lymphoma (DLBCL) andPMBCLshould be performed. Evaluation of the expression level of the genes JAK2, PDL1, PDL2, MAL, TRAF1 by polymerase chain reaction allows to different PMBCL and DLBCL. Diagnosis the PMBCL is established if detection of hyperexpression two or more genes. We did not find any publications with description of PMBCL with bone marrow involvement. We present here 2 clinical cases. Materials and methods: 154 patients with PMBCL treated in our center were examined. 16 (10,4%) of them had an extra-mediastinal localization. 2 patients (1,3%) were diagnosed with PMBCL with bone marrow involvement. Results: Case 1 A 42 years old female was hospitalized for vital indications with respiratory failure and syndrome of compression of the superior vena cava. In the mediastinum a tumor was 138x116.5 mm, involving the upper and middle lobes of the right lung. Tumor infiltrated the soft tissues of anterior wall of the chest, pericardium. The biopsy of the mediastinal tumor revealed the fragments of fibrous fat tissue with a dense infiltrate of medium size and large cells with oval nuclei, with one large or smalls nucleoli, a moderately pronounced light cytoplasm (Fig.1). Tumor cells expressed the CD20, PAX5, co-expressed CD23, CD30-, IgM-, Ki-67 80%. LDH level in blood was 578 E/l (208-378 E/l). International Prognosis Index (IPI) - 4. Peripheral blood was normal. Histology of the bone marrow showed diffuse interstitial infiltration by lymphoid cells of medium and large size with several small distinct nucleoli, mainly with the morphology of centroblasts, increased mitotic activity (Fig. 2). Tumor cells of bone marrow were CD20 +. Hyperexpression of JAK2, PDL1, TRAF1 genes in the bone marrow was revealed by PCR method. So the PMBCL was diagnosed. The patient received 6 courses of R-DA-EPOCH-21. At the end of treatment tumor lesions were still positive by PET/CT (Deauville score 5). The patient received the second line therapy, with HSCT. PET/CT was positive again (Deauville score 5). Hyperexpression of JAK2, PDL1, TRAF1 genes persisted in the bone marrow. The patient is alive now at 18 month from start of treatment. According to the CT there is no signs tumor progression. Case 2 B 69 years old female complained of weakness, profuse sweating, pain in the left scapular, temperature 38,0 C, weight loss by 11% of body weight, for the last 3 months. In the left hemithorax tumor mass of 135x67 mm, embracing the first rib with a pathological fracture. Tumor cells expressed CD20, PAX5, CD79α, TNFAI2, co-expressed CD23 and CD30, Ki-67 - 80%. LDH level in blood 994 E/l. IPI - 4. Peripheral blood was normal. Histological study of the bone marrow revealed a focal-interstitial lymphoid infiltration with small and medium sized cells with oval and irregularly shaped nuclei. Hyperexpression of the genes JAK2, MAL, TRAF1 was revealed in the bone marrow. The patient received 6 courses of R-DA-EPOCH-21. After the end of treatment FDG-PET/CT was positive (Deauville score 5). The patient received the second line therapy. After the treatment disease progression was established. Hyperexpression of JAK2, MAL, TRAF1 genes persisted in the bone marrow. The patient is alive now at 18 month from start of treatment, but with PMBCL. Conclusion: Both cases demonstrated resistant to R-DA-EPOCH lymphoma, though the frequency of complete remissions in patients with PMBCL is almost 90%. New approadies should be developed in such cases. Each year, with the accumulation of research data it became evident that within each well-defined nosological form there are borderline cases or those in which our understanding is insufficient to explain a particular phenomenon. The detection of bone marrow involvement in patients with PMBCL makes one think about the criteria for diagnosing the disease. Download : Download high-res image (228KB) Download : Download full-size image Disclosures No relevant conflicts of interest to declare.

Primary Mediastinal Undifferentiated Carcinoma Mimicking Type B Aortic Intramural Hematoma

Primary Mediastinal Undifferentiated Carcinoma Mimicking Type B Aortic Intramural Hematoma

Abstract 2657: PD-L1 blockade enhances T cell cytotoxicity against primary mediastinal B cell lymphoma

Abstract Background: Primary Mediastinal B cell Lymphoma (PMBL) represents 2-4% of Non-Hodgkin Lymphomas (NHL) in adolescents and young adults (AYA) (Gerrard/Cairo et al., Blood, 2013). Disease progression, relapse and long-term toxicity remain a concern for patients treated on current chemo-immunotherapy and mediastinal radiotherapy. Alternative therapeutic regimens are urgently needed, especially in patients without an early response to therapy. Programmed Death 1 (PD-1) is a negative co-stimulatory receptor critical for suppression of T-cell activation, with binding of PD-1 and Programmed Death Ligand 1 (PD-L1) resulting in T cell exhaustion (Postow/Wolchok et al., J Clin Oncol, 2015). Gain in 9p associated with amplification of PD-L1 has been reported in up to 60% of PMBL specimens, leading to overexpression of PD-L1 and potential immune cell evasion of PMBL (Rosenwald/Staudt et al., J Exp Med, 2003; Twa/Steidl et al., Blood, 2014). Blockade of PD-1/PD-L1 interaction, therefore, constitute a potentially promising alternative for treatment of resistant PMBL. Objective: In the current study, we sought to investigate whether PD-L1 blockade enhances T cell responses in PD-L1 expressing PMBL. Methods: PD-L1 expression on Karpas 1106p PMBL treated with or without IFN γ was investigated by western blotting and flow cytometry analyses. T cells were isolated from human PBMC followed by activation and expansion using anti-CD2, anti-CD3 and anti-CD28 Biotinylated MACSiBead particles. T cell activation was confirmed by CD25 and CD69 expression using flow cytometry. Activated T cells were incubated with or without anti-PD-L1 (Clone 6E11, Genentech) at a dose of 10 ug/ml together with Karpas 1106p cells treated with or without IFN γ. Cell proliferation was assessed with MTS assays after incubation for 24 hours. Results: We demonstrated that Karpas 1106p cells express a low level of PD-L1. However, following IFN γ treatment (48 hours) there was a significant increase in PD-L1 expression. Anti-PD-L1 had no significant effect on T cell mediated inhibition of cell proliferation in Karpas 1106p cells with low PD-L1 expression. However, anti-PD-L1 and T cell treatment significantly inhibited cell proliferation in IFN γ treated Karpas 1106p cells when compared to T cell treatment alone (32±18% vs. 3±3% at E:T=5:1, p=0.048). Conclusion: PD-L1 blockade enhances T cell cytotoxicity against PMBL, which is dependent on PD-L1 expression level on PMBL cells. Future in-vivo NSG xenograft studies are ongoing. Citation Format: Tishi Shah, Wen Luo, Aradhana Awasthi, Janet Ayello, Jessica Hochberg, Mitchell Cairo. PD-L1 blockade enhances T cell cytotoxicity against primary mediastinal B cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2657. doi:10.1158/1538-7445.AM2017-2657

Abstract 2652: Favorable outcome of primary mediastinal large B-cell lymphoma treated by Dose Adjusted EPOCH-Rituximab regimen

Abstract Background Primary Mediastinal Large B-Cell Lymphoma (PMLBCL) is a unique type of B-cell lymphoma probably arising from a putative thymic medulla B-cell. One to 2% of NHL, 7% of all diffuse large B-cell lymphomas (DLBCL), occurring more often in young females. Often presents with superior vena cava syndrome and airway compromise. Treatment is with chemotherapy combined with Rituximab, followed by involved field radiation therapy to mediastinum. PMLBCL has better outcome than others DLBCL. We aimed to develop a more dose-dense/intense regimens that improves the rate of cure with an attempt to avoid mediastinal radiation. Patients and methods A prospective study was conducted in our department from January to December 2015, in 6 patients with untreated primary mediastinal B-cell lymphoma. An infusional dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine, prednisone, and rituximab (DA-EPOCH-R) has been administred according to the protocol Day 1 : Rituximab 375 mg/m2 IV Day 1-4 : Etoposide 50 mg/m2 IV, Doxorubicin 10 mg/m2 AND Vincristine 0.4 mg/m2 Day 5 : Cyclophosphamide 750 mg/m2 Days 1-5 : Prednisone 60 mg/m2 PO BID. Administer G-CSF 5 mcg/kg SQ on day 6 until ANC exceeds nadir Cycles were repeated every 3 weeks for a toal of 6 cycles Results The median age of the patients was 32 years, the male to female ratio : 2:4. Systemic symptoms mainly fever and weight loss, were present in all cases; increased LDH levels were also observed in 50% of cases. Majority of the patients (83%) presented with stage I/II disease, bulky mass with a median tumor diameter 15 cm. Most had features of local extension like pleuro-pericardial effusion. Absence of infradiaphragmatic lymph nodes and no bone marrow involvement at presentation. All patients required biopsy from the mediastinal mass by image guided core biopsy. The patients were treated by RDA-EPOCH, they received 4 to 6 courses, without involved field radiotherapy (only one patient underwent radiotherapy for residual mass). No late morbidity or cardiac toxic effects were found in any patients. After 24 months of follow-up, one patient still received treatment and was not evaluable. 5 patients achieved complete remission and were disease-free at the last visit. Conclusion PMBCL is a specific lymphoma entity seen in the young with good survival. It has a distinct clinical behavior and prognosis, and therefore require a different therapeutic approach. The R/DA-EPOCH regimen need to be confirmed in further prospective study for a large cohort. Note: This abstract was not presented at the meeting. Citation Format: Fatiha Grifi, Soraya Bougherira. Favorable outcome of primary mediastinal large B-cell lymphoma treated by Dose Adjusted EPOCH-Rituximab regimen [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2652. doi:10.1158/1538-7445.AM2017-2652

Poor predictive value of positive interim FDG-PET/CT in primary mediastinal large B-cell lymphoma.

Though commonly used to assess response to therapy, the prognostic value of interim FDG-PET/CT in Primary Mediastinal Large B-cell Lymphoma (PMBCL) is unclear. We conducted a retrospective study on 36 consecutive patients treated at our institution for a PMBCL between 2006 and 2014. All patients with a positive interim FDG-PET/CT had undergone histological restaging consisting either in a surgical debulking of the residual lesion (15 patients) or a CT-guided core needle biopsy (two patients). All FDG-PET/CT were secondarily reviewed according to the more recent Deauville criteria. Interim FDG-PET/CT was considered positive in 17/36 patients using visual evaluation. Among these patients, 14 had a Deauville score of 4. Histological restaging was negative in all but one case, showing inflammation and/or fibrosis. After a median follow-up of 48.5months, a total of five patients have relapsed, two patients in the positive FDG-PET/CT group, and three patients in the negative FDG-PET/CT group, respectively. These data indicate that a positive interim FDG-PET/CT does not reflect persistence of active disease in the vast majority of PMBCL cases. The relapse rate appears similar regardless of interim FDG-PET/CT results and interpretation criteria. This suggests that interim FDG-PET/CT has a poor positive predictive value, thus kt should be used with caution in PMBCL.

English

English

Tracheobronchial Obstruction Caused by Primary Mediastinal Lymphoma

Tracheobronchial Obstruction Caused by Primary Mediastinal Lymphoma

Thymoma and Synchronous Primary Mediastinal Seminomas with Florid Follicular Lymphoid Hyperplasia in the Anterior Mediastinum: A Case Report and Review of the Literature.

Thymoma is the most common neoplasm of the anterior mediastinum and has malignant potential. Germ cell tumors (GCTs) found in the anterior mediastinum are usually benign, and malignant GCTs, such as seminomas, are rare. Histologically, mediastinal seminoma is indistinguishable from testicular seminoma except for site-associated morphological features such as lymphoid follicular hyperplasia. Therefore, excluding metastasis is very important. Recently, we treated a young adult patient with multiple thymic masses that occurred simultaneously. The patient underwent a thymectomy for the removal of the mediastinal masses, one of which was diagnosed as type B2 invasive thymoma, and two of which were diagnosed as primary mediastinal seminomas with massive follicular hyperplasia. The patient received adjuvant chemotherapy after surgical resection. To our knowledge, this is the first description of a thymoma and a mediastinal seminoma occurring simultaneously in the thymus. We present this case along with a literature review.