Magnetic Resonance Elastography of Anterior Mediastinal Tumors.

BACKGROUND: Preoperative differentiation of the types of mediastinal tumors is essential. Magnetic resonance (MR) elastography potentially provides a noninvasive method to assess the classification of mediastinal tumor subtypes. PURPOSE: To evaluate the use of MR elastography in anterior mediastinal masses and to characterize the mechanical properties of tumors of different subtypes. STUDY TYPE: Prospective. SUBJECTS: 189 patients with anterior mediastinal tumors (AMTs) confirmed by histopathology (62 thymomas, 53 thymic carcinomas, 57 lymphomas, and 17 germ cell tumors). FIELD STRENGTH/SEQUENCE: A gradient echo-based 2D MR elastography sequence and a diffusion-weighted imaging (DWI) sequence at 3.0 T. ASSESSMENT: Stiffness and apparent diffusion coefficients (ADC) were measured in AMTs using MR elastography-derived elastograms and DWI-derived ADC maps, respectively. The aim of this study is to identify whether MR elastography can differentiate between the histological subtypes of ATMs. STATISTICAL TESTS: One-way analysis of variance (ANOVA), two-way ANOVA, Pearson's linear correlation coefficient (r), receiver operating characteristic (ROC) curve analysis; P < 0.05 was considered significant. RESULTS: Lymphomas had significantly lower stiffness than other AMTs (4.0 ± 0.63 kPa vs. 4.8 ± 1.39 kPa). The mean stiffness of thymic carcinomas was significantly higher than that of other AMTs (5.6 ± 1.41 kPa vs. 4.2 ± 0.94 kPa). Using a cutoff value of 5.0 kPa, ROC analysis showed that lymphomas could be differentiated from other AMTs with an accuracy of 59%, sensitivity of 97%, and specificity of 38%. Using a cutoff value of 5.1 kPa, thymic carcinomas could be differentiated from other AMTs with an accuracy of 84%, sensitivity of 67%, and specificity of 90%. However, there was an overlap in the stiffness values of individual thymomas (4.2 ± 0.71; 3.9-4.5), thymic carcinomas (5.6 ± 1.41; 5.0-6.1), lymphomas (4.0 ± 0.63; 3.8-4.2), and germ cell tumors (4.5 ± 1.79; 3.3-5.6). DATA CONCLUSION: MR elastography-derived stiffness may be used to evaluate AMTs of various histologies. TECHNICAL EFFICACY: Stage 2.

Distinguishing thymic cysts from low-risk thymomas via [18F]FDG PET/CT.

BACKGROUND: Thymic cysts are a rare benign disease that needs to be distinguished from low-risk thymoma. [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is a non-invasive imaging technique used in the differential diagnosis of thymic epithelial tumours, but its usefulness for thymic cysts remains unclear. Our study evaluated the utility of visual findings and quantitative parameters of [18F]FDG PET/CT for differentiating between thymic cysts and low-risk thymomas. METHODS: Patients who underwent preoperative [18F]FDG PET/CT followed by thymectomy for a thymic mass were retrospectively analyzed. The visual [18F]FDG PET/CT findings evaluated were PET visual grade, PET central metabolic defect, and CT shape. The quantitative [18F]FDG PET/CT parameters evaluated were PET maximum standardized uptake value (SUVmax), CT diameter (cm), and CT attenuation in Hounsfield units (HU). Findings and parameters for differentiating thymic cysts from low-risk thymomas were assessed using Pearson's chi-square test, the Mann-Whitney U-test, and receiver operating characteristics (ROC) curve analysis. RESULTS: Seventy patients (18 thymic cysts and 52 low-risk thymomas) were finally included. Visual findings of PET visual grade (P < 0.001) and PET central metabolic defect (P < 0.001) showed significant differences between thymic cysts and low-risk thymomas, but CT shape did not. Among the quantitative parameters, PET SUVmax (P < 0.001), CT diameter (P < 0.001), and CT HU (P = 0.004) showed significant differences. In ROC analysis, PET SUVmax demonstrated the highest area under the curve (AUC) of 0.996 (P < 0.001), with a cut-off of equal to or less than 2.1 having a sensitivity of 100.0% and specificity of 94.2%. The AUC of PET SUVmax was significantly larger than that of CT diameter (P = 0.009) and CT HU (P = 0.004). CONCLUSIONS: Among the [18F]FDG PET/CT parameters examined, low FDG uptake (SUVmax ≤ 2.1, equal to or less than the mediastinum) is a strong diagnostic marker for a thymic cyst. PET visual grade and central metabolic defect are easily accessible findings.

A rare case of tumor-to-tumor metastasis from thymic carcinoma to an ovarian mature teratoma.

Metastasis from one neoplasm to another is referred to as tumor-to-tumor metastasis (TTM). TTM is rarely observed. Here, we present a patient with TTM from a thymic carcinoma to an ovarian mature teratoma. A 25-year-old woman, diagnosed with unresectable thymic carcinoma, presented with a cyst with a solid tumor component in her right ovary. Laparoscopic cystectomy of the right ovary revealed that the solid tumor was a distant metastasis of the thymic carcinoma in an ovarian mature teratoma. The possibility of malignant transformation of the ovarian mature teratoma was ruled out, enabling accurate staging of the thymic carcinoma. This case emphasizes the need for clinicians to consider TTM and the importance of pathological confirmation of TTM when investigating potential distant metastases.

Carcinoide atípico de timo en varón de 39 años: Reporte de caso / Atypical carcinoid of thymus in a 39-year-old-man: A case report

RESUMEN El carcinoide atípico (CA) de timo es la neoplasia más agresiva y rara que surge en el mediastino anterior y que pertenece a los tumores primarios neuroendocrinos de timo. La mayoría de los pacientes son asintomáticos y según la extensión de la enfermedad pueden presentar desde tos, disnea, dolor torácico hasta síndrome de vena cava superior. Esta presentación clínica inespecífica disminuye la probabilidad del diagnóstico temprano que, sumado con el estadio avanzado al debut y la imposibilidad de resección quirúrgica reduce la tasa de supervivencia. El objetivo es dar a conocer la presentación clínica, imagenológica y patológica en un varón de 39 años con CA de timo cuyo diagnóstico definitivo se basó en el estudio histopatológico (morfología carcinoide, mitosis 0-1/2 mm2, necrosis, Ki 67 = 12%) y marcadores inmunofenotípicos del tumor (CD 56 (+), Panqueratina (+), Sinaptofisina (+), TTF -1 (-)).

ABSTRACT The atypical carcinoid (AC) of thymus is the most aggressive and uncommon neoplasm in the anterior mediastinum, that belongs to the neuroendocrine primary tumors of thymus. Most patients are asymptomatic and according to the disease extension they may present with cough, dyspnea, chest pain, and superior cava vein syndrome. This non-specific clinical presentation reduces the likelihood for making an early diagnosis; and this, together with disease stage and lack of surgical resection reduces the survival rate. The aim of this paper is to describe the clinical presentation in a 39-year old male with thymus carcinoid whose diagnosis was based on histopathological studies (carcinoid morphology, 0-1/2 mitoses/mm2), necrosis, Ki67, 12%), and immunophenotypic tumor markers (CD56(+), Pankeratin (+), Synaptophysin (+), and TTF-1 (-)).

Congenital thymoma

Thymomas are a heterogeneous group of tumors arising from the epithelium of the thymus. They are categorized by the proportion of neoplastic epithelia to lymphocytes and by the degree of cytologic atypia. Thymomas constitute 0.2-1.5% of all malignancies and nearly all occur in patients over 20 years. We reviewed the available literature and found less than 50 cases of thymoma reported in children (<18 years of age), the youngest being 4 years old, and no cases in newborns. They represent less than 1% of all mediastinal tumors in children. Due to the limited number of cases in the pediatric population, the diagnosis and treatment in this population is extremely challenging. Thymomas in all age groups may be associated with paraneoplastic syndromes, being myasthenia gravis the most common, which is associated with a worse prognosis in the pediatric population. We present the first case of a newborn infant with congenital thymoma. This case demonstrates a rare tumor in an unusual age group and emphasizes the importance of multidisciplinary teamwork in the decision-making and management of this condition.

Robotic thoracic surgery for resection of thymoma and tumors of the thymus: technical development and initial experience / Cirurgia torácica robótica para ressecção de timoma e tumores tímicos: desenvolvimento técnico e experiência inicial

ABSTRACT Objective: To evaluate the results of resection of tumors of the thymus by robotic thoracic surgery, analyzing the extent of resection, postoperative complications, time of surgery, and length of stay. Methods: Retrospective study from a database involving patients diagnosed with a tumor of the thymus and undergoing robotic thoracic surgery at one of seven hospitals in Brazil between October of 2015 and June of 2018. Results: During the study period, there were 18 cases of resection of tumors of the thymus: thymoma, in 12; carcinoma, in 2; and carcinoid tumor, in 1; high-grade sarcoma, in 1; teratoma, in 1; and thymolipoma, in 1. The mean lesion size was 60.1 ± 32.0 mm. Tumors of the thymus were resected with tumor-free margins in 17 cases. The median (interquartile range) for pleural drain time and hospital stay, in days, was 1 (1-3) and 2 (2-4), respectively. There was no need for surgical conversion, and there were no major complications. Conclusions: Robotic thoracic surgery for resection of tumors of the thymus has been shown to be feasible and safe, with a low risk of complications and with postoperative outcomes comparable to those of other techniques.

RESUMO Objetivo: Avaliar os resultados da ressecção de tumores tímicos por cirurgia torácica robótica, verificando a radicalidade da ressecção, complicações pós-operatórias, tempo de cirurgia e tempo de internação. Métodos: Estudo retrospectivo a partir de um banco de dados envolvendo pacientes com diagnóstico de tumor tímico e submetidos à cirurgia torácica robótica em sete hospitais no Brasil entre outubro de 2015 e junho de 2018. Resultados: Durante o período estudado, houve 18 casos de ressecção de tumores tímicos (timomas, em 12; carcinoma tímico, em 2; e tumor carcinoide tímico, sarcoma tímico de alto grau, teratoma tímico e timolipoma, em 1 cada). A média do tamanho das lesões foi de 60,1 ± 32,0 mm. Tumores tímicos foram ressecados com margens livres em 17 casos. As medianas (intervalos interquartis) de tempo de dreno pleural e de internação, em dias, foram 1 (1-3) e 2 (2-4), respectivamente. Não houve necessidade de conversão cirúrgica nem complicações maiores. Conclusões: A cirurgia torácica robótica para a ressecção de tumores tímicos demonstrou ser factível e segura, com baixo risco de complicações e desfechos pós-operatórios comparáveis aos de outras técnicas.

Tumores del timo: Experiencia del Instituto Nacional de Cancerología de Colombia / Thymic tumors: Experience of the National Cancer Institute of Colombia

Resumen Objetivos: Los tumores del timo tienen incidencia global de 0,13 por 100.000 habitantes, pero representan un importante porcentaje de tumores del mediastino. Hay poca literatura basada en nuestra población, por esto, hacemos un aporte de nuestra experiencia en el Instituto Nacional de Cancerología (INC). Métodos: Se hizo un estudio tipo series de caso, revisando las historias clínicas de los pacientes con tumores del timo tratados en el INC entre 2006 y 2017. Resultados: Desde el 2006 al 2017 se encontraron 31 pacientes con tumores del timo tales como timoma, hiperplasia tímica, quistes tímicos y carcinomas tímicos, predominando en el género femenino y con una mediana de 62 años de edad. 2 pacientes presentaron miastenia gravis (MG). 27 fueron sometidos a timectomía por medio de esternotomía, videotoracoscopia, toracotomía, entre otros, obteniendo una supervivencia global mayor al 90% a 5 años de seguimiento. Los estadios de Masaoka I, II y III tienen mejor pronóstico que los tipos IV independientemente de la histología. Conclusiones: La timectomía es el tratamiento de primera línea en los casos resecables, incluso en los que existe compromiso de estructuras vecinas que permiten una resección quirúrgica completa. Los resultados presentados describen conductas y resultados similares a los encontrados en la literatura mundial.

Abstract Objectives: Thymic tumors have an overall incidence of 0.13 per 100,000 inhabitants, but they represent a significant percentage of mediastinal tumors. There is little literature based on our population, we make a contribution of our experience in the National Cancer Institute. Methods: We did a case series study, reviewing the clinical histories of patients with thymic tumors treated at the National Cancer Institute from 2006 to 2017. Results: From 2006 to 2017, 31 patients with thymic tumors such as thymoma, thymic hyperplasia, thymic cysts and thymic carcinomas were found, mainly in the female gender and with a median of 62 years of age. 2 patients presented Myasthenia Gravis (MG). 27 patients underwent thymectomy through sternotomy, video-thoracoscopy, thoracostomy among others, obtaining an overall survival greater than 90% at 5 years of follow-up. The stages of Masaoka I, II and III have a better prognosis than type IV regardless of the histological type. Conclusions: Thymectomy is the first-line treatment in resectable cases, even when there is a compromise of nearby structures that allow a complete surgical resection. Our results describe behaviors and results similar to those found in the world literature.

Quiste tímico multiloculado en un paciente adulto: presentación de caso y revisión de la literatura / Multiloculated thymic cyst in an adult patient: case report and literature review

Los quistes tímicos multiloculados son lesiones generalmente adquiridas, que se diagnostican de manera incidental en la mayoría de pacientes y se asocian con condiciones de naturaleza diversa, como: inflamación, infección, trauma y radioterapia. Se presenta el caso de una mujer de 55 años con un quiste tímico multiloculado, sin antecedentes de importancia o condición clínica particular al momento del diagnóstico.

Multiloculated thymic cysts are acquired lesions, diagnosed incidentally in most patients and associated with other conditions such as inflammation, infection, trauma and radiothera. We present the case of a 55-year-old woman with a multilocular thymic cyst, with no relevant history or particular clinical condition at the time of diagnosis.

Linfoma primario del mediastino (tímico): Presentación de caso / Primary Mediastinal Lymphoma (Thymic): A Case Report

Los linfomas mediastinales anteriores pueden hacer parte del linfoma sistémico y comprenden aproximadamente el 50 % de los tumores mediastinales. El linfoma no Hodgkin primario del mediastino es un subtipo de menor prevalencia, representando un 10 % de los casos; este tiene dos subtipos histológicos que son el linfoma T linfoblástico y el linfoma B difuso de célula grande. Este último es agresivo y tiende a infiltrar la pleura, las estructuras óseas y el pulmón; se origina de las células B de la médula del timo. En este artículo se describe un caso de linfoma no Hodgkin primario del mediastino del subtipo B difuso de células grandes, sus hallazgos por imágenes, patología y una breve revisión de la literatura.

Anterior mediastinal lymphomas may be part of systemic lymphoma and they comprise approximately 50 % of mediastinal neoplasms. Primary non-Hodgkin's lymphoma of the mediastinum is a subtype with lower prevalence, representing 10 % of all cases; it has two histologic subtypes that include T-cell lymphoblastic lymphoma and diffuse large B-cell lymphoma. The latter is an aggressive neoplasm that tends to infiltrate the pleura, bone structures and the lung; it originates from thymic medullary B cells. This article presents a case of primary non-Hodgkin's lymphoma of the mediastinum with diffuse large B-cell subtype, its radiologic findings, pathology and a brief review of the literature.

Thymoma followed by aplastic anemia: two different responses to immunosuppressive therapy

Aplastic anemia is an uncommon complication of thymoma and is extremely infrequent after the surgical removal of a thymic tumor. Aplastic anemia is a result of marrow failure and is characterized by peripheral pancytopenia and severely depressed marrow cellularity; it may be an autoimmune manifestation of thymoma. As thymoma-associated hematological dyscrasias, which include pure red cell aplasia, aplastic anemia and myasthenia gravis, are supposed to be of immunologic origin, two cases of very severe aplastic anemia following the resection of lymphocytic thymomas treated with immunosuppression are herein presented.

Tratamento cirúrgico da síndrome da veia cava superior causado por timoma invasivo / Surgical treatment of superior vena cava syndrome caused by invasive thymoma

Paciente do sexo masculino, branco, 57 anos, portador de síndrome da veia cava superior havia 3 meses, devido a timoma invasivo em mediastino médio e anterior, levando a comprometimento da veia cava superior intrínseca e extrinsecamente. Após avaliação por tomografia computadorizada e angiorressonância magnética de tórax, o paciente foi submetido à ressecção radical do timoma - derivação venosa da veia subclávia esquerda para átrio direito, com tubo de PTFE (politetrafluoroetileno). Relevante caso de timoma invasivo ocasionando a oclusão da veia cava superior. A evolução clínica, após 7 meses, foi considerada satisfatória.

We report on a case of a 57 years-old white male, patient, who presented superior vena cava syndrome (SVC) for 3 months, derived from an invasive thymoma in the medium and anterior mediastinum, compromising intrinsic and extrinsic to the SVC. After evaluation by computed tomography and magnetic angioresonance of the thorax, the patient underwent radical resection of the thymoma - bypass from left subclavian vein to right atrium, using polytetrafluoroethylene tube. Relevant case of invasive thymoma causing the occlusion of SVC. The clinic evolution of the patient after 7 months was considered satisfactory.

Asymptomatic giant mediastinal mass: a rare case of thymolipoma / Massa mediastinal gigante assintomática: um raro caso de timolipoma

Thymolipoma is a very rare benign neoplasm of the thymus. We present the case of a 42-year-old male with a massive mediastinal tumor discovered on a chest X-ray after a motorcycle accident. The patient had no complaints, and his physical examination was unremarkable. Chest CT scans revealed a lipomatous mass containing areas of soft tissue density. The patient was submitted to median sternotomy expanded to left anterolateral thoracotomy, resulting in the complete excision of the tumor. The pathological diagnosis was thymolipoma. Thymolipoma usually attains enormous dimensions by the time of diagnosis, and the occasional symptoms are related to compression of adjacent structures. Surgical resection is the treatment of choice and offers the only possibility of cure. The airway deserves special care during anesthesia induction.

Timolipoma é uma rara neoplasia benigna do timo. Apresentamos o caso de um paciente do sexo masculino de 42 anos de idade com um volumoso tumor mediastinal, descoberto após a realização de radiografia de tórax devido a um acidente motociclístico. Não apresentava queixas e ao exame físico não havia particularidades. A TC de tórax revelava uma massa lipomatosa entremeada por tecido com densidade de partes moles. O paciente foi submetido a uma esternotomia mediana com extensão para toracotomia ântero-lateral esquerda, permitindo a exérese completa do tumor. O diagnóstico histopatológico foi de timolipoma. O timolipoma geralmente atinge grandes dimensões na época do diagnóstico, sendo os ocasionais sintomas relacionados à compressão de estruturas adjacentes. A ressecção cirúrgica é o tratamento de escolha e a única possibilidade de cura. A via aérea merece atenção especial durante a indução anestésica.

Cisto tímico como diagnóstico diferencial de doença aguda da aorta torácica / Thymic cyst as a differencial diagnosis of acute thoracic aortic disease

Paciente encaminhada de outro serviço com história de dor torácica aguda de forte intensidade com diagnóstico de hematoma intramural na aorta ascendente para correção cirúrgica. Após investigação diagnóstica, identificou-se tumoração cística no mediastino anterior, que envolvia toda a aorta ascendente e que produzia restrição ao enchimento diastólico do ventrículo direito. A análise histológica do tumor ressecado revelou o diagnóstico de cisto tímico. Objetivo deste relato é descrever tumoração mediastinal de baixa prevalência, que pode produzir imagem radiológica com características de hematoma intramural e resultar em conduta terapêutica equivocada.

Patient was referred to our Service with acute thoracic pain and diagnosis of intramural hematoma of the ascending aorta for surgical correction. The diagnostic investigation showed a cystic tumor involving the ascending aorta causing restriction of the right ventricular inflow. After resection, the histologic analysis disclosed the diagnosis of thymic cyst. The aim of this study is to describe a rare mediastinal tumor that may simulate a radiologic feature with characteristics of intramural hematoma and may result in a wrong therapeutic approach.