Intrathymic Plasmablasts Are Affected in Patients With Myasthenia Gravis With Active Disease.

BACKGROUND AND OBJECTIVES: To investigate intrathymic B lymphopoiesis in patients with myasthenia gravis (MG) and explore thymus pathology associated with clinical impact. METHODS: Thymic lymphocytes from 15 young patients without MG, 22 adult patients without MG, 14 patients with MG without thymoma, and 11 patients with MG with thymoma were subjected to flow cytometry analysis of T follicular helper (Tfh), naive B, memory B, plasmablasts, CD19+B220high thymic B cells, B-cell activating factor receptor, and C-X-C chemokine receptor 5 (CXCR5). Peripheral blood mononuclear cells of 16 healthy subjects and 21 untreated patients with MG were also analyzed. Immunologic values were compared, and correlations between relevant values and clinical parameters were evaluated. RESULTS: The frequencies of circulating and intrathymic plasmablasts were significantly higher in patients with MG than controls. On the other hand, the frequency of CD19+B220high thymic B cells was not increased in MG thymus. We observed a significant increase in CXCR5 expression on plasmablasts in MG thymus and an increased frequency of intrathymic plasmablasts that was correlated with preoperative disease activity. The frequency of intrathymic Tfh cells was significantly lower in patients who received immunosuppressive (IS) therapy than those without IS therapy. However, there was no significant difference in the frequency of intrathymic plasmablasts irrespective of IS therapy. DISCUSSION: Our findings confirmed a correlation between increased frequency of intrathymic plasmablasts and disease activity before thymectomy. We postulate that activated intrathymic plasmablasts endow pathogenic capacity in MG.

Primary thymic adenocarcinoma with an aggressive clinical course: An autopsy case showing signet ring cell-like features.

Thymic adenocarcinoma is an extremely rare neoplasm, and little is known about its pathogenesis and clinical characteristics. A 52-year-old man presented to our clinic with severe dyspnea. At initial presentation, massive carcinomatous pleuritis and pericarditis were observed, and a lobulated mass in the anterior mediastinum was found on computed tomography. Cytological examination revealed adenocarcinoma accompanied by signet ring cells; however, his tumor showed aggressive growth without any possibility of treatment, and he died as a result of cancer progression within one month of admission. An autopsy confirmed thymic adenocarcinoma showing various histological features including mucinous, signet ring cell-like, and trabecular features. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) (AE1/AE3) but negative for TTF-1. In addition, some tumor cells were positive for CD5 and KIT. Further examination revealed that tumor cells of the nonmucinous type were positive for CK7, and negative for CK20 and caudal-type homeobox 2 (CDX2). The tumor cells with mucinous and signet ring-like features were positive for CK20 and CDX2 and negative for CK7, indicating enteric differentiation. In particular, tumor cells with signet ring cell-like features indicated widespread lymphangitic carcinomatosis and pulmonary tumor thrombotic microangiopathy (PTTM). The presence of signet ring cell-like features with enteric differentiation is suggestive of a fulminant clinical course due to widespread lymphangiosis carcinomatosa and PTTM in patients with thymic adenocarcinoma. KEY POINTS: Thymic adenocarcinoma is an extremely rare neoplasm. Histological features of thymic adenocarcinoma include mucinous, signet ring cell-like, and trabecular features. Tumor cells with signet ring cell-like features indicate widespread lymphangitic carcinomatosis and pulmonary tumor thrombotic microangiopathy. The presence of signet ring cell-like features with enteric differentiation is associated with a fulminant clinical course.

Improvement of reduced electroretinographic responses in thymoma-associated retinopathy: a case report and literature review.

PURPOSE: To report a patient with thymoma-associated retinopathy presenting as having a good visual prognosis. METHODS: Case report and literature review. CASE REPORT: A 42-year-old female patient was referred to our hospital for complaints of sudden visual-field defects bilaterally. Decimal corrected visual acuity (VA) was 1.5 and 1.2 in the right (RE) and left eyes (LE), respectively. Fundus autofluorescence revealed hyper-autofluorescence from the posterior pole to mid-peripheral retina in both eyes. Full-field electroretinography (ERG) amplitudes were reduced to 20-50% and 30-50% of our controls for the scotopic and photopic conditions, respectively. A systemic examination revealed the presence of thymoma, and the patient underwent thymectomy and immunosuppression therapies. Immunohistochemical analysis using the patient's serum showed immunolabeling on the photoreceptor inner segment and outer plexiform layer in the monkey retina. Two years later, VA remained at 1.5 and 1.2 in RE and LE. ERG amplitudes improved to 30-60% of the controls for the scotopic conditions. However, photopic ERG showed no remarkable change. CONCLUSIONS: To our knowledge, improvement of reduced rod-mediated ERG responses has not been described in seven previously reported patients with thymoma-associated retinopathy. The good visual prognosis of our patient may be associated with well-timed intervention.

A ring-calcified thymoma, mimicking pericardial cyst, precedes pure red cell aplasia for more than 10 years - A case-based overview of pathophysiology.

Pure red cell aplasia (PRCA) is a rare disease characterised by anaemia and low reticulocyte count, caused by absence of erythropoiesis in the bone marrow. This report describes a case of a ring-calcified thymoma that led to the development of PRCA. Moreover, we provide an overview on the classification of thymoma and the pathophysiology and treatment of PRCA.

Implementation of proton therapy treatments with pencil beam scanning of targets with limited intrafraction motion.

PURPOSE: To report on the implementation, validation and results of the first two proton therapy PBS treatments of limited amplitudes moving targets performed at our center. METHODS AND MATERIALS: A real time optical tracking system was used to monitor the patient surface during the CT scan and treatment. This system is also able to trigger the beam during the treatment. A 4DCT (10 phases) and a Free-Breathing CT (FBCT) were used for the planning. The physician used the 4DCT for ITV delineation, while planning was performed on the FBCT. The approved plan was evaluated in two ways:The largest breathing amplitude recorded during 4DCT scan was used as gating safety threshold during treatment delivery. This planning and treatment workflow was then applied for two patients affected by thoracic thymoma. RESULTS: The dosimetric evaluation of the plan showed no interplay effect. The second patient showed an overdosage to the coronary and Left Anterior Descending area in the worst case scenario but it was below the constraints. Duty Cycle together with number of beam interruptions gave information about the patient compliance to the treatment: the first patient breath is stable and within thresholds, whilst the second patient had more variations, causing multiple beam interruptions. CONCLUSION: We defined and used for two patients a protocol for the treatment of small amplitude moving targets. The planning and delivery of the treatments gave very good results in terms of coverage, OARs sparing, 4D dose evaluation of the plan and interplay effect assessment.

Favourable health-related quality of life reported in survivors of thymic malignancies.

OBJECTIVES: The management of patients with locally advanced thymic malignancies remains controversial. Differing combinations of surgical resection, chemotherapy and radiation are used in the management of initial and relapsed disease. Treatment-related toxicities and quality of life could inform therapeutic options. This study describes health utility scores (HUS) in survivors with locally advanced thymic malignancies and investigates the impact of multimodality regimens on HUS. METHODS: In a cross-sectional study (2014-2017), patients with Masaoka Stage II-IVa thymic malignancies completed various self-reported questionnaires, including EuroQol-5-Dimensions with visual analogue scale (VAS), Eastern Cooperative Oncology Group (ECOG) and Edmonton Symptom Assessment Scale tools. Trimodality versus uni- or bimodality regimens and aggressive versus non-aggressive management of recurrent disease were compared using regression analyses. RESULTS: Of the 72 patients, 43 (60%) were male with a median age of 58 years, 65 (90%) had thymoma while 7 (10%) had thymic carcinomas; and median time since diagnosis was 50.5 months (range: 3-266). Median HUS and VAS did not differ between groups (trimodality n = 24 vs uni- or bimodality n = 48: HUS = 0.77 vs 0.80, P = 0.29; VAS = 80 vs 75, P = 0.79, respectively). The distributions of patient-reported ECOG were also similar (P = 0.86). Edmonton Symptom Assessment Scale scores for every assessed symptom were similar for different modalities of therapy. Median scores on these tools were also similar regardless of recurrence status or management of relapsed disease (aggressive versus non-aggressive). CONCLUSION: Survivors with Stage II-IVa thymic malignancies report favourable HUS, VAS and self-reported ECOG with minimal symptom burden. These outcomes may be independent of number and type of initial treatment modalities or management of recurrence.

Novel MRI of mediastinal masses: internal differentiation of a thymoma and lymphoma with T1 and T2 mapping.

Routine imaging for mediastinal malignancies includes chest X-ray, CT or MRI. T1 and T2 mapping are novel MRI techniques which may have a role in expanding the assessment of internal tumour characteristics. This case report details two middle-aged women who had similar clinical presentations of mediastinal masses of comparable size and appearance when assessed with routine imaging. T1 and T2 maps were acquired on MRI to investigate whether these tumours could be further differentiated prior to surgery. T1 and T2 mapping supported suspicion for which tumour components were solid and cystic, as subsequently confirmed histologically. Furthermore, comparison between the two tumours showed native T1 values differed within the solid components by 37%, correlating to differences in proteinaceous material within the tumour types. This radiological-pathological correlation provides evidence that T1 and T2 mapping has clinical utility in the assessment and differentiation of mediastinal masses.

Sclerosing thymoma: A rare case report and brief review of literature.

RATIONALE: Sclerosing thymoma is an extremely rare mediastinal neoplasm; it was recognized for the first time in 1994 and to date only 15 cases have been reported. PATIENT CONCERNS: The present study report a case of a 65-year-old man who was incidentally found to have an anterior mediastinal nodule, without clinical symptoms including fever, chest pain, and myasthenia gravis. DIAGNOSES: The chest computed tomography (CT) revealed the nodule was 4.9 × 4.2 × 3.0 cm in size. And the microscopic and immunohistochemical findings indicated that the final diagnosis was sclerosing thymoma. INTERVENTIONS: The anterior mediastinal nodule was completely removed. OUTCOMES: No evidence of recurrence or complication was found in the second year after surgery. LESSONS: The biologic behavior of the rare sclerosing thymoma is still largely mysterious; it is utmost importance to classify the sclerosing thymoma from other mediastinal tumors. Its prognosis is favorable and thymectomy is currently the mainstay of treatment.

Lupus Nephritis with Thymoma Managed by Thoracoscopic Surgery and Prednisolone.

A 48-year-old woman was admitted to our hospital to undergo evaluation for fatigue, severe weight loss, and nephrotic range proteinuria. Light microscopy of a renal biopsy specimen revealed class III (A) lupus nephritis, while immunofluorescence and electron microscopy only showed sparse immune deposits with findings that were not typical of lupus nephritis. Computed tomography revealed a mass in the anterior mediastinum, which was resected. The examination of the surgical specimen revealed type A noninvasive thymoma. In combination with thymomectomy, postoperative steroid therapy achieved the prompt remission of lupus nephritis. In this patient, thymoma-related autoimmunity may have contributed to the exacerbation of lupus nephritis.

Interstitial fluid pressure of thymic epithelial tumours.

Tumours show an increased interstitial fluid pressure, which correlates with various pathophysiological features. Moreover, interstitial fluid pressure is a prognostic factor for cervical and lung cancer. However, there have been no reports on the usefulness of measuring interstitial fluid pressure in thymic epithelial tumours. Therefore, this study aimed to examine the relationship between interstitial fluid pressure and the clinicopathological characteristics of thymic epithelial tumours. Interstitial fluid pressure was prospectively measured at the centre of the tumour using a 1-Fr Mikro-Tip sensor catheter in 44 patients with thymic epithelial tumours, 40 with thymomas and 4 with thymic carcinomas. Data from these 44 patients were analysed for correlations between interstitial fluid pressure and clinicopathological and demographic factors including sex, age, tumour size, World Health Organization histological subtypes, myasthenia gravis, capsular invasion, mediastinal pleura invasion, lung invasion, pericardium invasion, dissemination, Masaoka-Koga stage, maximal standardized uptake value and recurrence-free survival (RFS). The mean interstitial fluid pressure was 11.3 mmHg; interstitial fluid pressure was significantly correlated with maximal standardized uptake value, lung invasion, dissemination and Masaoka-Koga stage. Low interstitial fluid pressure (≤14 mmHg) showed a tendency for better RFS compared with high interstitial pressure (P = 0.053). Lung invasion, dissemination and Masaoka-Koga stage were correlated with RFS in univariable analysis; lung invasion was selected as an independent prognostic factor in multivariable analysis. On the basis of these results, interstitial fluid pressure of thymic epithelial tumours has been shown to correlate with their clinicopathological features.

Thymic large cell neuroendocrine carcinoma - a rare and aggressive tumor: a case report.

BACKGROUND: Neuroendocrine tumors are a large group of tumors with a wide spectrum of behavior, affecting mainly the digestive system and the lung. The thymus is very rarely affected. CASE PRESENTATION: A 28-year-old Arab woman presented with chronic chest pain and dyspnea. A computed tomography scan showed a huge anterior mediastinal mass invading neighboring structures. A mediastinotomy was performed with biopsies of the mass. Pathological findings were consistent with a thymic large cell neuroendocrine carcinoma. CONCLUSIONS: The occurrence of a large cell neuroendocrine carcinoma in the thymus, especially in young people, is extremely rare. In this current report, we discuss the clinicopathological issues of this rare tumor according to recent literature data.

Thymic Neuroendocrine Neoplasms: Biological Behaviour and Therapy.

Thymic neuroendocrine neoplasms are rare tumours, but their management can often be highly problematic. While previously assumed to be essentially variants of bronchopulmonary (lung) carcinoids, they are generally more aggressive and more difficult to treat. Some 25% are associated with multiple endocrine neoplasia-1, while a higher proportion are associated with the ectopic ACTH syndrome, and occasionally both. We discuss the classification of these tumours, their biology as far as is known, and their clinical, biochemical and imaging features. We also review possible management options and suggest stratagems to optimise their treatment, which even today is far from optimal.

Condensin II mutation causes T-cell lymphoma through tissue-specific genome instability.

Chromosomal instability is a hallmark of cancer, but mitotic regulators are rarely mutated in tumors. Mutations in the condensin complexes, which restructure chromosomes to facilitate segregation during mitosis, are significantly enriched in cancer genomes, but experimental evidence implicating condensin dysfunction in tumorigenesis is lacking. We report that mice inheriting missense mutations in a condensin II subunit (Caph2nes) develop T-cell lymphoma. Before tumors develop, we found that the same Caph2 mutation impairs ploidy maintenance to a different extent in different hematopoietic cell types, with ploidy most severely perturbed at the CD4+CD8+ T-cell stage from which tumors initiate. Premalignant CD4+CD8+ T cells show persistent catenations during chromosome segregation, triggering DNA damage in diploid daughter cells and elevated ploidy. Genome sequencing revealed that Caph2 single-mutant tumors are near diploid but carry deletions spanning tumor suppressor genes, whereas P53 inactivation allowed Caph2 mutant cells with whole-chromosome gains and structural rearrangements to form highly aggressive disease. Together, our data challenge the view that mitotic chromosome formation is an invariant process during development and provide evidence that defective mitotic chromosome structure can promote tumorigenesis.

Postoperative Recurrence of Invasive Thymoma with Cold Agglutinin Disease and Autoimmune Hemolytic Anemia.

A 50-year-old man presented to our hospital in 1995. Invasive thymoma was diagnosed and extended thymectomy and left upper lobe partial resection were performed. In 2013, he complained of dyspnea. Chest computed tomography showed postoperative recurrence of invasive thymoma. Several chemotherapies were administered. Severe anemia and an increase in the total bilirubin level were observed with chemotherapies. In additional, an examination showed that the direct Coombs test was positive. Cold agglutinin was also high. We herein experienced a rare case of postoperative recurrence of invasive thymoma with cold agglutinin disease and autoimmune hemolytic anemia.

Expression of cell cycle and apoptosis regulators in thymus and thymic epithelial tumors.

The human thymus supports the production of self-tolerant T cells with competent and regulatory functions. Various cellular components of the thymic microenvironment such as thymic epithelial cells (TEC) and dendritic cells play essential roles in thymic T cell differentiation. The multiple cellular events occurring during thymic T cell and TEC differentiation involve proteins regulating cell cycle and apoptosis. Dysregulation of the cell cycle and apoptosis networks is involved in the pathogenesis of thymic epithelial tumors (TET) which are divided into two broad categories, thymomas and thymic carcinomas. The present review focuses on the usefulness of the analysis of the expression patterns of major cell cycle and apoptosis regulators in order to gain insight in the histophysiology of thymus and the histopathology, the clinical behavior and the biology of TET.

Initial Experience of 18F-FDG PET/MRI in Thymic Epithelial Tumors: Morphologic, Functional, and Metabolic Biomarkers.

PURPOSE: The aim of this study was to investigate the value of morphologic, functional, and metabolic biomarkers acquired concurrently at PET/MRI in patients with thymic epithelial tumors. PATIENTS AND METHODS: During 1 year, 9 patients with suspected thymic epithelial tumors at contrast-enhanced chest CT were prospectively enrolled and underwent preoperative 18F-FDG PET/MRI. Two chest radiologists prospectively reviewed the CT and MRI scans of PET/MRI in consensus, and 2 nuclear physicians reviewed the PET images. Visual assessment of the tumor morphology, functional biomarkers such as apparent diffusion coefficient from diffusion-weighted images, and metabolic biomarkers (including SUVmax, metabolic tumor volume, total lesion glycolysis, and heterogeneity index) were recorded. All patients underwent operation, and their pathologic reports served as the reference standard. RESULTS: Thymic epithelial tumors were demonstrated in all 9 patients at pathologic examination. Tumor contour (P = 0.012) and shape (P = 0.033) had an association with the World Health Organization subtype, and the presence of septum (P = 0.048) on MRI scans had an association with the Masaoka stage. In terms of functional and metabolic biomarkers, SUVmax (ρ = 0.683, P = 0.042) and SUV/apparent diffusion coefficient (ρ = 0.703, P = 0.035) correlated with the Masaoka stage. Metabolic tumor volume (P = 0.024), heterogeneity index (P = 0.024), and total lesion glycolysis (P = 0.048) were useful for classification between low- and high-risk thymic epithelial tumors. CONCLUSIONS: Although limited by the small number of patients enrolled, morphologic, functional, and metabolic biomarkers derived from PET/MRI scans were useful for the stratification of thymic epithelial tumors.

Low-dose radiation-induced enhancement of thymic lymphomagenesis in Lck-Bax mice is dependent on LET and gender.

The hypothesis that mitochondrial dysfunction and increased superoxide levels in thymocytes over expressing Bax (Lck-Bax1 and Lck-Bax38&1) contributes to lymphomagenesis after low-dose radiation was tested. Lck-Bax1 single-transgenic and Lck-Bax38&1 double-transgenic mice were exposed to single whole-body doses of 10 or 100 cGy of (137)Cs or iron ions (1,000 MeV/n, 150 keV/µm) or silicon ions (300 MeV/n, 67 keV/µm). A 10 cGy dose of (137)Cs significantly increased the incidence and onset of thymic lymphomas in female Lck-Bax1 mice. In Lck-Bax38&1 mice, a 100 cGy dose of high-LET iron ions caused a significant dose dependent acceleration of lymphomagenesis in both males and females that was not seen with silicon ions. To determine the contribution of mitochondrial oxidative metabolism, Lck-Bax38&1 over expressing mice were crossed with knockouts of the mitochondrial protein deacetylase, Sirtuin 3 (Sirt3), which regulates superoxide metabolism. Sirt3(-/-)/Lck-Bax38&1 mice demonstrated significant increases in thymocyte superoxide levels and acceleration of lymphomagenesis (P < 0.001). These results show that lymphomagenesis in Bax over expressing animals is enhanced by radiation exposure in both an LET and gender dependent fashion. These findings support the hypothesis that mitochondrial dysfunction leads to increased superoxide levels and accelerates lymphomagenesis in Lck-Bax transgenic mice.

Cisplatin and irinotecan combination chemotherapy for advanced thymic carcinoma: evaluation of efficacy and toxicity.

BACKGROUND: Thymic carcinoma is a rare, malignant mediastinal tumor that is definitively distinguished from thymoma by its wide extensiveness and poor prognosis. At present, cisplatin-based triplet or quartet chemotherapy with the second generation antitumor agents, referred to as Einhorn's protocol for germ cell tumors, is used as first-line chemotherapy for advanced thymic carcinoma, though an optimal chemotherapeutic regimen has not yet been established. In this retrospective study, the effectiveness and toxicity of cisplatin and irinotecan combination chemotherapy were evaluated over a nine-year period. PATIENTS AND METHODS: Patients with advanced thymic carcinoma who were treated with cisplatin and irinotecan combination chemotherapy between January 1, 2002 and December 31, 2010, were retrospectively identified from our database and medical records. The endpoints in this study were disease control, response rate, progression-free survival (PFS), and overall survival (OS). Significant hematological and non-hematological toxicities were also assessed. RESULTS: Among identified nine patients, disease control was achieved in 8 patients (88.9%), and a clinical response was achieved in 5 (55.6%). The median PFS was 7.9 months, and the median OS was 33.8 months. One- and two-year OS were 77.7% and 55.6%, respectively. Grade 3/4 hematological toxicities were observed in 2 patients (22.2%), and Grade 3/4 non-hematological toxicities were seen in 2 patients (22.2%). No febrile neutropenia or toxic death was recorded. CONCLUSION: Cisplatin and irinotecan combination chemotherapy appears to be acceptable for advanced thymic carcinoma as first-line chemotherapy with respect to efficacy, toxicity, and usage in the clinical setting.