Mediastinal masses in children

[18F]fluorodeoxyglucose positron emission tomography/computed tomography characteristics of primary mediastinal germ cell tumors

Primary mediastinal germ cell tumor (MGCT) is an uncommon tumor. Although it has histology similar to that of gonadal germ cell tumor (GCT), the prognosis for MGCT is generally worse than that for gonadal GCT. We performed visual assessment and quantitative analysis of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) for MGCTs. A total of 35 MGCT patients (age = 33.1 ± 16.8 years, F:M = 16:19) who underwent preoperative PET/CT were retrospectively reviewed. The pathologic diagnosis of MGCTs identified 24 mature teratomas, 4 seminomas, 5 yolk sac tumors, and 2 mixed germ cell tumors. Visual assessment was performed by categorizing the uptake intensity, distribution, and contour of primary MGCTs. Quantitative parameters including the maximum standardized uptake value (SUVmax), tumor-to-background ratio (TBR), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum diameter were compared between benign and malignant MGCTs. On visual assessment, the uptake intensity was the only significant parameter for differentiating between benign and malignant MGCTs (p = 0.040). In quantitative analysis, the SUVmax (p < 0.001), TBR (p < 0.001), MTV (p = 0.033), and TLG (p < 0.001) showed significantly higher values for malignant MGCTs compared with benign MGCTs. In receiver operating characteristic (ROC) curve analysis of these quantitative parameters, the SUVmax had the highest area under the curve (AUC) (AUC = 0.947, p < 0.001). Furthermore, the SUVmax could differentiate between seminomas and nonseminomatous germ cell tumors (p = 0.042) and reflect serum alpha fetoprotein (AFP) levels (p = 0.012). The visual uptake intensity and SUVmax on [18F]FDG PET/CT showed discriminative ability for benign and malignant MGCTs. Moreover, the SUVmax may associate with AFP levels.

Application of computer-assisted surgery in pediatric mediastinal tumor surgery

BACKGROUND

Computer-assisted Surgery system (CAS) is an effective medical imaging simulation tool, which is widely used in preoperative planning of surgery. The objective of this study is to investigate the clinical application of CAS in pediatric mediastinal tumor resection.

METHODS

This retrospective study investigated 74 children who underwent mediastinal tumor resection between June 2008 and June 2022 at the pediatric surgical center of the Affiliated Hospital of Qingdao University and Qingdao Women and Children's Hospital. Preoperative chest computed tomography imaging was performed on all children. A total of 44 children (the CAS-assisted group) underwent clinical image 3D reconstruction and preoperative simulation using Hisense CAS. The control group consisted of 30 children who underwent a conventional procedure without CAS. The demographic, preoperative, and complication data were analyzed and compared between the two groups. t-test, Mann-Whitney U test, X² test, or Fisher's exact test were used accordingly in this study during analysis.

RESULTS

The median operative duration was 119.00 min in the CAS-assisted group and 140.50 min in the control group. The median intraoperative blood loss of the CAS-assisted group and the control group was 14.00 and 31.00 ml respectively. Relative to the control groups, the CAS-assisted group experienced shorter operative duration time (p = 0.041), and less intraoperative blood loss (p < 0.001). The difference in postoperative drain indwelling between the CAS-assisted group (median:4.00 days) and the control group (median:7.00 days) reached a statistical significance (p = 0.001). And the duration of hospitalization after the operation for the CAS-assisted group (median:7.00 days) was shorter than that for the control group (median:9.00 days) (p = 0.001). No significant difference could be found in the rate of blood transfusion (p = 0.258) and the incidence of postoperative complications (p = 0.719) between the two groups.

CONCLUSION

Hisense CAS could effectively assist surgeons to clearly determine the anatomical site of tumors and provide accurate preoperative simulation for surgeons, so as to assist surgeons to specify effective surgical plans for patients.

A Multidisciplinary Surgical Approach to Mediastinal Masses in Children

The aim of this study is to demonstrate the safety and advantages of a multidisciplinary approach to surgical resection of mediastinal masses in children. Eight patients underwent resection of a mediastinal mass by a team involving both a pediatric general surgeon and pediatric cardiothoracic surgeon. One patient required rapid initiation of cardiopulmonary bypass to complete the tumor resection and repair an aortic injury that occurred when removing adherent tumor from the structure. Perioperative outcomes were excellent for all patients. This series shows that a multidisciplinary surgical approach can be potentially life saving.

A 14-Year-Old Female With Chest Mass, Shortness of Breath, and Hypertension

BACKGROUND

A previously healthy 14-year-old girl was evaluated in the emergency department (ED) with 2 months of shortness of breath and fatigue.

METHODS

She initially presented to her primary pediatrician, where a complete blood count was only significant for mild anemia, thyroid function tests were normal, and a chest x-ray revealed a chest mass. This prompted her primary pediatrician to order a computed tomography scan and refer to the ED.

RESULTS

Her computed tomography scan confirmed a mediastinal mass versus necrotic lymphadenopathy. Her initial physical exam was unremarkable, except for hypertension. From the ED, she was admitted to the pediatric hospital medicine service. Infectious disease, oncology, and nephrology services were consulted to guide diagnostic evaluation.

CONCLUSIONS

Eventually, during her hospitalization, further history and workup led to a definitive diagnosis.

Pediatric mediastinal masses

Mediastinal masses are categorized based on the International Thymic Malignancy Interest Group (ITMIG) classification into prevascular, visceral and paravertebral compartments. The schema is based on cross-sectional imaging, mainly CT, and helps with generating a differential diagnosis based on location of the mass. Up to half of all pediatric mediastinal tumors are malignant. In this review we describe mediastinal masses that are relevant to the pediatric population, as well as the role of MR imaging of mediastinal masses and its advantages.

Pediatric sudden unexpected death due to undiagnosed mediastinal T-cell lymphoblastic lymphoma: A series of three cases

The literature on pediatric sudden unexpected death (SUD) due to unrecognized mediastinal neoplasms is limited to a small number of case reports with several cases confirmed to be secondary to T-cell lymphoblastic lymphoma (T-cell LBL). Mediastinal T-cell LBL can be rapidly progressive and potentially fatal due to the compression and obstruction of the airway and/or the great vessels. The clinical presentation is nonspecific with a predominance of respiratory symptoms that are more apparent when the patient is supine. We presented three cases of pediatric SUD attributed to forensic autopsy-diagnosed anterior mediastinal T- cell LBL. Case 1 involved a 2-year-old girl who presented with 9 days of cough and dyspnea. Postmortem examination revealed a firm rubbery mass surrounding the heart and compressing the bronchi. Case 2 involved a 3-year-old girl who suffered from a respiratory tract infection over several days. Autopsy revealed a firm nodular mass compressing the superior vena cava. Case 3 involved a 2-year-old boy who was found unresponsive, lying prone in his crib. He had cold-like symptoms for several days before his death. Postmortem examination revealed a firm, rubbery anterior mediastinal neoplasm surrounding the superior vena cava and great arteries. These three cases demonstrate the importance of identifying children with mediastinal masses that could potentially lead to life-threatening presentations and pediatric SUD. The forensic pathologist should consider a hematologic neoplasm at the time of autopsy in a previously healthy child who dies suddenly.

The Relevance of Preoperative Identification of the Adamkiewicz Artery in Posterior Mediastinal Pediatric Tumors

Background

Injury to the artery of Adamkiewicz (AKA) during surgery may lead to spinal cord ischemia and severe neurologic complications. Posterior mediastinal tumors may be adjacent to AKA, but data on preoperative visualization of AKA in children are rare. This study analyzed the importance of identifying the AKA preoperatively by spinal digital subtraction angiography (DSA) in children with posterior mediastinal tumors for therapeutic procedure.

Methods

Between 2002 and 2021, 36 children with posterior mediastinal tumors were evaluated for surgery at the authors’ clinic. In 10 children with left-sided or bilateral tumor located at vertebral levels T8 to L1, spinal DSA was performed during preoperative workup to assess AKA. The patient and tumor characteristics as well as the diagnostic and therapeutic procedures were analyzed.

Results

The median age of the 10 children at examination was 69 months (range, 16–217 months). Three of the children were younger than 2 years. The tumor entities were neuroblastoma, ganglioneuroblastoma, ganglioneuroma, local relapse of a hepatocellular carcinoma, and neurofibroma. The AKA was identified in all cases, and proximity to the tumor was detected in four patients, three of whom had their planned surgery changed to irradiation. No complications occurred during spinal DSA or surgery.

Conclusions

In posterior mediastinal pediatric tumors, spinal DSA is a safe and reliable method for preoperative visualization of the AKA. It can show proximity to the tumor and guide the local therapy, thereby avoiding critical intra- and postoperative situations.

Cardiomegaly Masquerading as a Pediatric Thymoma: A Case Report

Thymoma is a very rare pediatric tumor, accounting for less than 1% of all childhood mediastinal tumors with scant literature, and only 23 pediatric cases were identified by a pediatric tumor surveillance registry between 1973 and 2008. In contrast to adult thymomas, pediatric thymomas have an aggressive tendency, though the majority is discovered as incidental findings. Patient presentations to the emergency department (ED) are often subtle and non-specific such as dyspnea, cough, and chest pain, requiring a broad differential on the part of the emergency clinician. Because of this presentation, diagnosis often occurs later in the disease process when compared with adults. Chest radiograph may demonstrate an enlarged thymic shadow or cardiomegaly, necessitating further cardiac workup, commonly routed through cardiology. Computed tomography and biopsy are required for definitive diagnosis, requiring a multidisciplinary approach to management. We present a case of a 16-year-old female complaining of progressive dyspnea and chest pain over the course of one to two months with radiographic cardiomegaly. She was found to have a Masaoka stage III World Health Organization (WHO) type B3 thymic endothelial neoplasm and underwent surgical resection.

Anterior mediastinal masses - A multidisciplinary pathway for safe diagnostic procedures

OBJECTIVE

The objective of this study was to report our multidisciplinary diagnostic approach for patients with anterior mediastinal masses (AMM).

METHODS

A retrospective review of patients with AMM at a tertiary pediatric surgical oncology centre (January 2011-December 2016) was performed. We analyzed data on clinical presentation, mode of tissue diagnosis, anesthetic techniques, and complications.

RESULTS

Of the 44 patients admitted with AMM (median age 11 years, 27 males and 17 females), 22 had respiratory symptoms. Imaging revealed tracheobronchial compression in 26 children. Twenty patients had a lymph node biopsy. Ten patients had image-guided core biopsy of the mediastinal mass, and 2 had mediastinoscopic biopsy of a paratracheal lymph node. One patient with likely recurrence of a relapsed metastatic ethmoid carcinoma did not have a biopsy. The diagnosis was made from alternative tissues, such as pleural fluid in 4 and peripheral blood in 7 patients. Twenty-five anesthetics were assessed, as 14 patients required no or only local anesthesia, and 5 had unavailable anesthetic notes. Eighteen of 25 patients were anesthetized maintaining spontaneous breathing, mostly by means of ketamine sedation. There were no major anesthetic complications.

CONCLUSION

Safe tissue diagnosis of anterior mediastinal masses can be obtained by a personalized multidisciplinary approach. Use of alternative tissues, local anesthesia, and ketamine sedation help minimize the need for general anesthesia, muscle paralysis, and controlled ventilation.

LEVEL OF EVIDENCE

IV (Case Series with no Comparison Group).

Magnetic resonance imaging of the pediatric mediastinum

The mediastinum, the central anatomical space of the thorax, is divided by anatomical landmarks but not by physical boundaries. The mediastinum is a conduit, a space through which cranial nerves, important nerve branches, the sympathetic chain, vascular structures, and visceral structures, the trachea and esophagus pass. This arrangement allows contiguous extension or communication of disease along facial planes and through potential spaces to and from the head and neck or cervical spine, to and from the superior mediastinum, between superior and inferior mediastinal levels, and between inferior mediastinal spaces into the intra- and retroperitoneal spaces. Magnetic resonance imaging (MRI) of the mediastinum in children poses technical challenges, in particular cardiac and respiratory motion, and diagnostic challenges, including a broad range of tissue types and possible diagnoses. In this paper we review mediastinal anatomy, MRI sequences and protocol choices and include a short discussion of features and MRI findings of some of the congenital and acquired pathologies that are most often encountered in the pediatric mediastinum.

Mediastinal lesions across the age spectrum: a clinicopathological comparison between pediatric and adult patients

The objective of this study was to identify the differences in histopathological distribution and clinical features of mediastinal lesions (MLs) across the age spectrum in Chinese series of patients and to compare with the available literature. A total of 409 cases of MLs, including 137 pediatric and 272 adult patients from a single institution, was reviewed and categorized into groups according to age. Among the 409 cases, the age showed a bimodal distribution with an increased incidence of MLs among (< 10 year) and (60–< 70 year) age groups. Thymic lesions, neurogenic tumors, and cysts made up 57% of MLs among the 409 cases. A significantly higher frequency was found for neurogenic tumors, germ cell tumors, mesenchymal tumors, and lymphatic lesions, (p < 0.01) for all, in pediatric population compared to adults. On the contrary, frequencies of thymic lesions and metastatic carcinomas were significantly higher in adults compared to pediatric category, (p < 0.01) for both. Overall, 41.6% were asymptomatic, however, pediatric patients showed a significantly higher incidence of cough and fever, (p < 0.01) for both, and dyspnea (p = 0.02), than adults. Whereas adult subset showed a significantly higher incidence of chest pain (p = 0.02), or oppression (p < 0.01), than pediatric counterpart. In conclusion, the age spectrum was the factor that influenced the histopathological distribution and the clinical presentation of MLs in Chinese series of patients. Such differences might be considered in the differential diagnosis and therapeutic approach for adult as well as pediatric patients with MLs. Furthermore, our study was comparable to the literature in terms of MLs frequencies.

Magnetic resonance imaging of the mediastinum, chest wall and pleura in children

The acceptance of applications for the use of chest MRI in children has been somewhat slow and selective. The use of MRI to image chest wall lesions is likely the most common and widely used indication, aside from the widespread and somewhat sophisticated use of MRI in imaging the cardiovascular structures of the chest. In this respect, fairly standard variations of T1-W, T2-W and contrast-enhanced imaging can be used, similar to the sequences used for musculoskeletal lesions elsewhere in the body. Imaging of the anterior mediastinal masses should be performed in conjunction with a detailed pre-test clinical examination to determine potential cardiovascular compromise. MRI in the setting of middle mediastinal adenopathy, congenital mediastinal cysts or posterior mediastinal masses, however, has been shown to be more effective and more comprehensive than multidetector CT. Although sonographic imaging is the initial modality of choice for pleural abnormalities, MR imaging is extremely effective and clinically useful in the setting of a potentially ambiguous sonographic examination. Faster imaging protocols are likely to increase the acceptance of MRI to replace multidetector CT for many pediatric chest lesions.

Pediatric thymomas: report of two cases and comprehensive review of the literature

PURPOSE

Thymomas are rare pediatric malignancies with indolent behavior. There are fewer than 50 reported cases and no comprehensive review. We sought to evaluate our recent experience with pediatric thymomas, and comprehensively review the extant literature.

METHODS

A systematic search of the PubMed database was performed using keywords: "thymoma", "pediatric", "juvenile", "childhood", and "child". Additional studies were identified by a manual search of the reference list.

RESULTS

We report two patients with thymomas. We identified 22 case reports or series that described 48 patients; 62 % were male, 15 % presented with myasthenia gravis. Fifty percent were Masaoka Stage I, 15 % were Stage II, 13 % were Stage III, and 23 % were Stage IV. Four patients with early stage (I or II) disease were treated with adjuvant therapies in addition to surgical excision, while five patients with late stage (III or IV) disease treated with surgical excision alone. Of studies reporting at least 2-year follow-up, survival was 71 %.

CONCLUSION

Pediatric thymomas are rare tumors with a slight male predominance. Wide variations were observed in the treatment of thymomas across all stages. Our review indicates a need for large database and multi-institutional studies to clearly elucidate clinical course, prognostic factors and outcome.

Tuberculosis of the thymus in a 6-month-old infant with literature review

Tuberculosis of the thymus is very uncommon. Most previously reported cases have involved adolescents or adults. Herein, we report a case of tuberculosis of the thymus diagnosed in a 6-month-old infant, presenting with progressive dyspnea and a mediastinal mass. Both clinical and radiologic findings were nonspecific, while pathologic findings confirmed thymic tissue with massive caseous granulomas consistent with tuberculosis.

Timely identification of children with cancer

Background. Cancer in childhood is rare, but nevertheless one of the most frequent causes of disease related death. Initial symptoms are often unspecific, frequently leading to a delay of cancer diagnosis. As a timely diagnosis can be crucial for the clinical outcome, our aim is to point out when unspecific symptoms should be considered suspect of being associated with specific cancer entities. Data sources. A systematic literature research in PubMed and current biliographies, as well as an evaluation of published epidemiologic data was performed. Results. This article reviews the typical presenting features and epidemiologic characteristics of the more common childhood malignancies, elucidates when specific and virtually unspecific symptoms require further evaluation, and gives advice how to start a rational diagnostic workup. Furthermore, genetic syndromes requiring increased watchfulness for cancer in childhood are demonstrated. Conclusion. Patients showing suspect symptoms should early be referred to specialized centres to assure optimal diagnostic and therapeutic capabilities.

MR imaging of the chest in children

The application of magnetic resonance imaging (MRI) to diseases of the pediatric chest has been complicated, selective and cautious. More specifically, MRI of the pediatric lung has been a highly anticipated technique that has inherent great potential for improved imaging of the chest without the use of ionizing radiation. Practical issues impede the transition from multidetector computed tomography (MDCT) to MRI in some chest diseases in children, while other disease states are intrinsically easier to image using MRI. More rapid respiratory and cardiac rates, patient instability, sedation requirements, and the low physical density of water in the lung, hinder the requirement for maximal spatial and contrast resolution. This review is intended to serve as a functional review of the practical and currently applicable ways in which the transition of imaging the non-cardiac aspects of the pediatric chest from MDCT to MRI can be done in a clinically useful way.

Mediastinal masses in children: experience with 120 cases

Primary mediastinal malignancies are rare tumors and can originate from any mediastinal organ or tissue such as thymic, neurogenic, lymphatic, germinal, or mesenchymal. The authors reviewed all cases of primary pediatric mediastinal masses diagnosed over a 25-year period to determine the pattern of presentation, the histology, and the outcome of the surgical treatment. In this study, 120 primary pediatric mediastinal mass cases diagnosed between 1985 and 2011 are retrospectively evaluated according to their age, sex, symptoms, anatomical location, surgical treatment, and histopathological evaluation. The median age of the patients was 5.8 years. There were 34 benign and 86 malign tumors. Thirty patients were asymptomatic. Common symptoms in the patients were cough, dyspnea, fatigue, fever, abdomen pain, back pain, and neurological symptoms. According to their origins, they were presented as neurogenic tumors (38.3%), lymphomas (18.3%), undifferentiated sarcomas (15%), germ cell tumors (7.5%), and the other tumors (22%) thymic pathologies, lymphangiomas, rhabdomyosarcomas, lipomas, hemangiomas, and Wilms' tumor. Complete resection of the tumor was performed in 86 patients, partial resection of the tumor was the intervention in 11 patients. In 23 patients, biopsy was undertaken. Because of the high incidence of asymptomatic or nonspecific presentation such as the upper airway disease, the presentation of a mediastinal mass in children may be challenging. Neurogenic tumors or lymphomas are indicating surgery, if possible complete resection, for both benign and malignant conditions. Although surgery is the mainstay of therapy for most mediastinal tumors, an experienced multidisciplinary approach is necessary.