Epithelial thymic tumours in paediatric age: a report from the TREP project

Thymic carcinoma presenting with overlap polyarthritis and myositis: A rare paraneoplastic syndrome in childhood

Thymic tumors are very rare neoplasms in children and account for less than 1% of mediastinal tumors in pediatric patients. One-third of the pediatric patients present with symptoms related to the compression of the tumor mass on the surrounding anatomic structures, and paraneoplastic syndromes such as myasthenia gravis, pure red cell aplasia, acquired hypogammaglobulinemia, and connective tissue disorders, which rarely occur in children with thymic tumors. Herein, we report a case of thymic carcinoma mimicking the symptoms of a connective tissue disease with symmetrical polyarthritis accompanying myositis, fever, weight loss, and malaise in a 15-year-old male patient. To our knowledge, this is the first case pediatric thymic carcinoma accompany with severe polyarthritis and myopathy, thus we have reviewed the current literature regarding the cases of thymic malignancies coexisting with paraneoplastic syndromes in children.

Pediatric Thymoma: A Review and Update of the Literature

Pediatric thymomas are extremely rare and slow-growing malignant tumors. The recent publication of the first Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) Tumor–Node–Metastasis (TNM) stage classification and updated treatment guidelines for thymomas has prompted us to perform a review of the literature on pediatric thymomas. A search of English-language articles in the PubMed, Cochrane, Web of Science, and Embase databases was conducted. Additional articles were identified through reference lists of retrieved publications. Thirty-two articles involving 82 pediatric thymomas were included. Males comprised 60% of patients, and 13% manifested myasthenia gravis (MG). Histotype B1 (45%) and stage I (52% Masaoka–Koga and 71% UICC/AJCC TNM) were the most frequent. Of note is the possibility that the lack of cases with mixed histologies in the reviewed publications might be related to a sampling issue, as it is well known that the more sections are available for review, the more likely it is that the majority of these neoplasms will show mixed histologies. Both staging systems showed a gradual increase in the percentage of cases, with more advanced stages of disease moving from type A to B3 thymomas. Complete surgical resection (R0) was the main therapeutic approach in Masaoka–Koga stage I (89%) and UICC/AJCC TNM stage I (70%) thymomas. Advanced stages of disease and incomplete surgical resection were most often associated with recurrence and death. An association between stage and outcome, and completeness of resection and outcome, was found. Interestingly, though an association between histotype and staging was found, this does not take into account the possibility of mixed histologies which would reduce the clinical impact of histologic subtyping over staging.

The Use of Sunitinib as Maintenance Therapy in a Pediatric Patient With a Poorly Differentiated Thymic Carcinoma

BACKGROUND

Thymic carcinomas are rare aggressive mediastinal tumors with a median survival of 2 years.

OBSERVATION

We present a pediatric patient who was diagnosed with metastatic thymic carcinoma and showed continuous improvement of his primary mass and lung metastases with a regimen of cisplatin/docetaxel followed by long-term maintenance therapy with sunitinib for over 5 years.

CONCLUSIONS

This report demonstrates a long-term positive treatment effect using chemotherapy followed by sunitinib in an advanced thymic carcinoma. We are not aware of other reports of pediatric patients with metastatic thymic carcinoma treated with sunitinib maintenance who maintained a durable response for this prolonged period of time.

Thymic Tumours in Children

Thymomas are very rare neoplasms in children and they represent less than 1% of mediastinal tumours in the paediatric population. The aim of our study was to assess the long-term treatment results of children with thymic tumours. A total number of eight children (four boys and four girls) with thymic tumours were identified. Median age at diagnosis was 7 years. In seven of them, thymoma was diagnosed; in one, a thymic carcinoma was diagnosed. In five of them, the WHO type was assessed: in two of them, the B1 type was found; in one, B2 was found; in one, AB was found, and in one, C was found. In all but one, surgery was the first-line treatment, but six patients had only partial resection. One patient started treatment with chemotherapy and four others received chemotherapy after the surgery. Radiotherapy was applied in six patients, with a median total dose of 37.5 Gy. Follow-up ranged from 8.5 to 273.5 months, with a median of 6.1 years. During this time, four patients died: one due to progression of the disease, and in the other three, the reason for death was unknown. In all evaluated patients, complete regression was observed (100% local control). Two-, 5- and 10-year OS and PFS were 85% and 72%, 51% and 54%, 51% and 54%, respectively. Combined treatment could provide satisfactory results in thymoma patients. There is a need for further, larger studies, which could help to establish optimal management strategies.

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.

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.

The Role of a Good Quality Autopsy in Pediatric Malpractice Claim: A Case Report of an Unexpected Death in an Undiagnosed Thymoma

Thymomas are extremely rare in the first 20 years of life, with different clinical presentations: from asymptomatic mediastinal masses to compressive and paraneoplastic syndromes. In pediatric population, the respiratory disorders have a higher incidence. The overall thymoma mortality rate is described as 40% and metastasized tumors are more aggressive. This case report describes a compressive syndrome caused by a thymoma in which symptoms were exacerbated by a concurrent pulmonary infection, thus leading an affected infant to sudden death despite medical treatment. In this case, patient's death occurred just before the differential diagnostic process got completed. Malpractice claim was based on the missing diagnosis as well as the suspect of inadequate provided care. Consequently, autopsy played a crucial post-mortem role to find out the cause of death, and to exclude any professional liability. Despite modern diagnostic techniques, autopsies are still the best available forensic tool. It is useful to remember that death is a fact of life, therefore not always preventable.

Thymic lesions of the paediatric age group: a comprehensive review of non-neoplastic and neoplastic etiologies

Thymus is an important part of the immune system of the paediatric age group. Thymic lesions are rare causes of anterior mediastinal pathology. Their occurrence in children is rarer, nevertheless, knowledge about their pathologies help in clinching the correct diagnosis. All lesions both non-neoplastic as well as neoplastic are found in children, however, they differ from adults not only in the clinical presentation but also in the pathogenesis and natural history of the disease. Thymic hyperplasia may not actually be true if age is taken into consideration. Similarly, a type B thymoma may be mistakenly diagnosed as a lymphoblastic lymphoma especially on small biopsies. This review has been carried out after extensive search of literature using the Google and Pubmed search engines. An attempt has been made to comprehensively cover all aspects of thymic pathology of the paediatric age group having historical significance as well as the recent updates.

Rare Tumors in Children: Progress Through Collaboration

Rare pediatric tumors account for approximately 10% of all childhood cancers, which in themselves are a rare entity. The diverse histologies and clinical behaviors of rare pediatric tumors pose challenges to the investigation of their biologic and clinical features. National and international cooperative groups such as the Rare Tumor Committee of the Children's Oncology Group, Rare Tumors in Pediatric Age Project, and European Cooperative Study Group for Pediatric Rare Tumors have developed several initiatives to advance knowledge about rare pediatric cancers. However, these programs have been only partially effective, necessitating the development of alternative mechanisms to study these challenging diseases. In this article, we review the current national and international collaborative strategies to study rare pediatric cancers and alternative methods under exploration to enhance those efforts, such as independent registries and disease-specific, National Cancer Institute-sponsored clinics.

Surgical management of thymic epithelial tumors in children: lessons from the French Society of Pediatric Oncology and review of the literature

PURPOSE

We report the results of a French multicenter retrospective study based on a period of more than 30 years and a review of the literature in order to more clearly define the surgical approach and specific pediatric risk factors.

METHODS

Clinical data of children comprising all histologic subtypes of thymic epithelial tumors (TET) treated between 1979 and 2009 in French pediatric oncology centers were retrospectively analyzed and discussed in the light of a review of all pediatric cases reported in the literature.

RESULTS

Nine cases were identified, corresponding to five females and four males with a median age of 13 years (range: 7.5-17). Histologic subtypes were type AB (n = 1), type B (n = 5) and type C (n = 3). Treatment consisted of tumor resection (4 R0, 4 R1, 1 R2) via right anterior thoracotomy, posterolateral thoracotomy, left thoracoscopy, sternotomy and cervicosternotomy, and/or chemotherapy, mainly cyclophosphamide-doxorubicin-cisplatin (CAP; n = 5), and/or radiotherapy (n = 4). Two patients with TET type C died. All other patients are alive with a median follow-up of 4 years (range: 1.5-20). Review of a total of 93 pediatric cases reported in the literature showed statistically significant associations between less favorable histologic subtypes and male gender (P = 0.012), advanced Masaoka stage (P < 0.001) and quality of resection (P < 0.001) respectively.

CONCLUSIONS

A review of the literature and our series identified several risk factors to take into account in the therapeutically decision. Complete resection through a sternotomy is highly recommended.

Rare childhood tumors in a Turkish pediatric oncology center

Background:

It has been estimated that rare tumor rate is about 15% of all childhood cancer in United States. According to Turkish Pediatric Oncology Group (TPOG) datas, 8889 children were diagnosed between 2002 and 2008 in our country and 3.7% of them were diagnosed as rare tumors.

Aim:

To investigate the frequency and clinical features of rare tumors in our pediatric oncology center.

Materials and Methods:

A total of 43 cases that have diagnosed as rare tumor in 574 cancer patients between the yaer 2002 and 2012 were reviewed retrospectively. All cases definitive diagnosis were established by histopathological and immunohistochemical studies.

Results:

Frequency of rare tumors was 7.4% in our center. Benign and border line rare tumors were 27 (62.7%) cases, malignant rare tumor were 16 (37.2%) cases. Median follow-up period was 48 months (between 1 and 110 months). Six of the malignant rare tumors were died with progressive disease (synovial sarcoma, mixed malignant mesenchymal tumor, undifferentiated sarcoma, plexus choroideus carcinoma, renal peripheral primitive neuroectodermal tumor, adrenocortical carcinoma). Malignant rare tumor mortality rate was found 37.5% in our clinic.

Conclusion:

We have found that our rare tumor rate (7.4%) was higher than Turkish rare tumor rate (3.7%) according to TPOG's datas. However, it was still lower than rare tumor rates of western countries (15%), probably due to difficulties of diagnosis and referral problems.