Mediastinal tumors in children

Abstracts

BACKGROUND: Mediastinal tumors in children comprise a heterogeneous group of lesions that have a range of embryonic origins. They may present as benign cysts, as well as malignant lesions. OBJECTIVE: To describe the diagnostic procedures, the treatments and outcomes of a group of children and adolescents with mediastinal tumors. METHOD: A retrospective analysis of twenty children and adolescents with mediastinal tumors who were treated at the Hospital de Clínicas de Porto Alegre from July, 1996 to July, 2002. All patients were submitted to some kind of surgical procedure: diagnostic, therapeutic, or both. RESULTS: Twelve boys and eight girls were studied. Mean age at diagnosis was 6 years and 8 months (ranging from 3 months to 16 years). Fourteen tumors (70%) were located at the anterior, and six (30%) at the posterior mediastinum. Hodgkin and non-Hodgkin lymphomas were the most common tumors found in anterior mediastinum, whereas neuroblastoma was the most common among posterior malignancies. The most used surgical procedure for anterior tumors was Chamberlain anterior thoracotomy; posterolateral thoracotomy was usually performed for posterior tumors. Six patients died during the follow-up period but none of the deaths was considered related to the surgical procedure. CONCLUSION: Mediastinal tumors in children and adolescents represent an important cause of morbidity/mortality. The most common tumors at the anterior mediastinum were lymphomas, whereas at the posterior mediastinum the most common were neurogenic tumors. Surgery is an important step for the diagnosis and treatment of such lesions

Tumors; Mediastinum; Child; Lymphoma

INTRODUÇÃO: Os tumores mediastinais na criança compreendem um grupo heterogêneo de lesões com origem embrionária distinta. Podem apresentar-se como cistos benignos ou lesões malignas. OBJETIVO: Descrever os procedimentos diagnósticos, tratamento e evolução de uma série de crianças e adolescentes com tumores do mediastino. MÉTODO: Análise retrospectiva de vinte crianças com tumores de mediastino, no período de julho de 1996 a julho de 2002 no Hospital de Clínicas de Porto Alegre. Todos os pacientes foram submetidos a algum procedimento cirúrgico, seja diagnóstico, terapêutico ou ambos. RESULTADOS: Doze meninos e oito meninas foram estudados. A idade média no momento do diagnóstico foi de seis anos e oito meses, variando entre três meses e 16 anos. Quatorze tumores (70%) ocorreram no mediastino anterior, sendo os mais comuns os linfomas de Hodgkin e não-Hodgkin; seis tumores (30%) ocorreram no mediastino posterior, sendo o neuroblastoma o mais freqüente. Nos tumores anteriores, a abordagem cirúrgica mais comum foi a toracotomia anterior de Chamberlain; nos posteriores, a toracotomia póstero-lateral. No período de seguimento ocorreram seis óbitos, todos sem nenhuma relação com o procedimento cirúrgico. CONCLUSÃO: Os tumores mediastinais em crianças são responsáveis por morbimortalidade. No mediastino anterior foram mais comuns os linfomas; no posterior, os tumores de origem neural. A cirurgia é um passo importante no diagnóstico e tratamento dessas lesões

Tumores; Mediastino; Criança; Linfoma

ORIGINAL ARTICLE

Mediastinal tumors in children^*

José Carlos Fraga^I; Marcia Komlós^II; Eliziane Takamatu^III; Luciano Camargo^III; Fábio Contelli^III; Algemir Brunetto^IV; Carlos Antunes^V

^IAssociate Professor of Pediatric Surgery

^IIMedical Student

^IIIResident Doctor of Pediatric Surgery

^IVAssociate Professor of Pediatrics. Head of the Pediatric Oncology Department

^VAssociate Professor of Pediatric Surgery . Head of the Department of Pediatric Surgery

^{Correspondence}

ABSTRACT

BACKGROUND: Mediastinal tumors in children comprise a heterogeneous group of lesions from a range of embryonic origins. They may present as benign cysts or malignant lesions.

OBJECTIVE: To describe the diagnostic procedures, the treatments and outcomes in a group of children and adolescents with mediastinal tumors.

METHODS: A retrospective analysis of twenty children and adolescents with mediastinal tumors who were treated at the Hospital de Clínicas de Porto Alegre from July 1996 to July 2002. All patients were submitted to surgery, either diagnostic, therapeutic or both.

RESULTS: A total of 12 boys and 8 girls were studied. Mean age at diagnosis was 6 years and 8 months (range: 3 months to 16 years). Of the 20, 14 (70%) presented tumors in the anterior mediastinum and 6 (30%) in the posterior. In the anterior mediastinum, Hodgkin's and non-Hodgkin's lymphoma were the most common tumors, whereas neuroblastoma was the most common posterior malignancy. The surgical procedure most commonly used for anterior tumors was Chamberlain anterior thoracotomy and posterolateral thoracotomy was usually performed for posterior tumors. During the follow-up period, 6 patients died but all of the deaths were judged to be unrelated to the surgical procedure.

CONCLUSION: Mediastinal tumors in children and adolescents result in significant morbidity and mortality. Lymphoma is more common in the anterior mediastinum- and neurogenic tumors are more common in the posterior mediastinum. Surgery is an important measure used in the diagnosis and treatment of such lesions.

Key words: Tumors. Mediastinum. Child. Lymphoma/surgery

Abbreviations used in this paper:

HCPA – Hospital de Clínicas de Porto Alegre

HL – Hodgkin’s lymphoma

NHL – non-Hodgkin’s lymphoma

PNET – Primitive neuroectodermal tumor

Introduction

Mediastinal tumors in children comprise a range of lesions that have their origin in the embryonic tissues.⁽¹⁾ Their presentation varies from benign cysts to very aggressive malignant lesions. Despite being rare, these tumors are responsible for significant morbidity and mortality in children and adolescents.^(2,3) There have been no studies describing the most frequent mediastinal lesions in children and addressing diagnostic approach, treatment and outcome.

In order to accurately diagnose mediastinal tumors in children, it is important to understand the complex anatomy of the mediastinum and the prevalence of each type of tumor depending upon anatomical location and the age of the child.⁽¹⁾ The clinical manifestations of these lesions are non-specific and, due to the fact that the mass expands within a limited area, compression of adjacent structures is generally seen. The most common respiratory manifestations are cough, dyspnea, hemoptysis and recurrent respiratory infections. Other symptoms that may occur are dysfagia, chest pain and fever.^(1,3)

Surgery is fundamental in the management of mediastinal masses, either for biopsy used to establish the etiology of the tumor and devise a course of therapy or for curative resection.^(1,3)

In this study, we reviewed the cases of children and adolescents treated for mediastinal tumors at our University Hospital. Our objective was to diagnose the lesion, determine an appropriate approach and surgical procedure, assess the need for complementary treatment and evaluate the outcome.

Method

From July 1996 to July 2002, 10 cases of mediastinal tumors were treated at the Pediatric Oncology Department of the Hospital de Clínicas de Porto Alegre (HCPA). A retrospective evaluation of these children was undertaken. Medical charts were reviewed and data such as type and site of the tumor, age at which diagnosis was made, radiological exams performed, staging, type of surgery performed, surgical complications, adjuvant therapy, post-operative outcome and follow-up were analyzed.

Depending on their mediastinal location, the tumors were classified as anterior, middle or posterior. Patients with tumors in the chest wall or pulmonary parenchyma were excluded. The Hospital de Clínicas is a Pediatric Oncology reference for the state of Rio Grande do Sul and for the entire southern region of Brazil.

Results

We analyzed 20 cases of children with mediastinal tumors. The mean age at time of diagnosis was 6 years and 8 months (range: 3 months to 16 years).

The patient characteristics are described in Table 1. In 14 patients, the tumor was located in the anterior mediastinum and in 6 patients the tumor was in the posterior mediastinum. In this series, we observed no tumors in the middle mediastinum. All patients were submitted to chest X-ray and computed tomography. Magnetic resonance imaging was used in only one patient as a preoperative evaluation of a suspected neuroblastoma. The surgical procedure was diagnostic in 14 patients (70%) and therapeutic in 6 (30%). A child who had thoracoabdominal neuroblastoma (Table 1 - Nº 17) initially underwent laparotomy and biopsy of a non-resectable tumor. After chemotherapy, which achieved significant reduction of the tumoral mass, the tumor was resected through posterolateral thoracotomy. The choice of surgical procedure depended on the type and location of the tumor. The type of chemotherapy was chosen based on pathological diagnosis of the lesion according to the guidelines of the Pediatric Oncology Department.

The mean follow-up period was 16 months (range: 1–207 months). Treatment was discontinued in 6 patients who continue to be tumor-free, 8 patients are still being treated but exhibit no signs of disease, and 6 patients died. These deaths were due to progression of the primary disease or to chemotherapy-related toxicity and were all unrelated to the surgical procedure.

Of the 14 patients with anterior mediastinal tumors, 10 (71%) had lymphoma – 7 were non-Hodgkin’s lymphoma (NHL) and 3 were Hodgkin’s lymphoma (HL) – and the remaining 4 (29%) had various other tumors: cystic hygroma, teratoma, carcinoid tumor of the thymus and thymolipoma. Of the 7 NHLs, 4 were lymphoblastic, 2 were Burkitt’s and 1 was a large cell NHL. The surgical approaches to these tumors are presented in Table 1. In 11 of the anterior mediastinal tumor cases, only biopsy was performed. These biopsies were obtained through: 5 Chamberlain anterior thoracotomies, 2 incisions above the sternal notch, 2 sternotomies, 1 posterolateral thoracotomy and 1 videothoracoscopy. The 2 cases in which incision above the sternal notch was employed were those in which the patients were found to have bulky and protuberant mediastinal masses in the supra-sternal region.

In the remaining 3 patients with anterior mediastinal tumors, surgery to excise the lesion completely was performed – 2 through anterolateral thoracotomy and 1 through sternotomy (Table 1). In all 7 cases of NHL, the treatment consisted of surgical biopsy followed by chemotherapy. Of these 7 patients, 2 died, but the deaths were unrelated to the surgery. In the 3 cases of HL, biopsy was also performed; 2 of these patients were treated with chemotherapy and 1 was treated with a combination of chemotherapy and radiotherapy. All 3 died as a result of the primary disease. In the other anterior mediastinal tumor cases, outcomes were positive (Table 1).

There were 6 cases of posterior mediastinal tumor: 3 neuroblastomas, 1 ganglioneuroma, 1 ganglioneuroblastoma and 1 primitive neuroectodermal tumor (PNET). In all of these patients, the surgical approach to tumor excision was posterolateral thoracotomy (Table 1). In one of these cases, the tumor was thoracoabdominal and laparotomy was therefore performed in order to obtain a biopsy prior to the thoracotomy. Of these 6, 1 patient with neuroblastoma died 40 days after the biopsy due to clinical complications unrelated to the surgery (Table 1).

Discussion

The type and incidence of mediastinal tumors in childhood vary according to the location of the tumor and the age of the patient.⁽²⁾ Adequate pre-operative evaluation helps a physician decide if the appropriate approach is biopsy or resection.

Our data are in agreement with those found in the literature, confirming that lymphoma is the most common type of mediastinal tumor in children. Approximately one-third of all NHLs occur in the mediastinum and approximately two-thirds of patients with HL present mediastinal nodes.^(4,5) In patients with suspected lymphoma, mediastinal biopsy is necessary when biopsy of the peripheral nodes or other more accessible sites is not possible. ^(1,3)

In this series, diagnosis of the anterior mediastinal tumors was made based on clinical signs and radiographs. All patients underwent computed tomography scans to determine the site and extension of the lesion and to rule out other causes of mediastinal masses. In such cases, computed tomography is clearly indicated and should always be performed.^{(2, 6, 7)} As shown in our study, although occurring in a fewer cases, other tumors such as teratoma, cystic hygroma and malignancies of the thymus can also appear in the anterior mediastinum.^(8-11)

Lesions of the posterior mediastinum and paravertebral space comprise a heterogeneous group of neoplasias.^(12,13) The most commonly found neoplasias are neuroblastomas, ganglioneuromas or ganglioneuroblastomas and originate in the sympathetic ganglion. In a study by Saez et al. involving 63 patients with posterior mediastinal masses, 89% were of neural origin and neuroblastoma was the most common.⁽¹²⁾ In patients with localized tumors, complete surgical removal is associated with high levels of survival, and these levels are significantly higher in children with thoracic lesions than in children with abdominal lesions.^(2,12,13) In these posterior mediastinal tumors, as with anterior mediastinal tumors, computed tomography is necessary to determine the extent of the lesion. However, magnetic resonance imaging may be useful, especially in assessing infiltration of the medullary canal.⁽²⁾ Bone scan and bone marrow aspirates are essential to the staging of malignant tumors since, in patients with metastatic disease, chemotherapy should be performed prior to removal of the primary lesion.⁽¹²⁾ In our cohort of patients, all of the posterior mediastinal tumors were neural in origin: 3 neuroblastomas, 1 ganglioneuroma and 1 ganglioneuroblastoma. Of the 3 cases of neuroblastoma, 1 patient died, 1 is in remission and under observation, and 1 is still receiving chemotherapy but shows no sign of disease. In the cases of ganglioneuroma and ganglioneuroblastoma, outcomes were favorable; after four years of follow up, these 2 patients are currently disease-free.

In the surgical approach to mediastinal tumors in children, it is fundamental that the utmost care be taken in the use of anesthesia and tracheal intubation, especially in children with masses in the anterior mediastinum or severe respiratory symptoms.^(1,6) Supine positioning and absence of spontaneous breathing may provoke compression of the airways by the tumor, resulting in complete airway obstruction and subsequent respiratory failure. It is important that the surgeon, the anesthesiologist and the oncologist be aware of this possibility and use care when anesthetizing or handling these patients. Many times, the physician should look for extrathoracic tumors, which, when present, should be biopsied under local anesthesia. This may confirm the diagnosis, allowing chemotherapy to be immediately initiated and sparing the patient the invasive intrathoracic procedures.^(1,6)

As observed in our study, surgical access to the mediastinum is obtained using various techniques. The most commonly described techniques are thoracoscopy, mediastinoscopy and thoracotomy – the last being anterior (Chamberlain procedure), anterolateral or posterolateral. In cases of mediastinal tumors, thoracoscopy has been used as both a diagnostic and a therapeutic measure and has become increasingly more common as surgeons have gained confidence in the procedure. Studies have shown that tissue samples obtained through thoracoscopy are adequate for diagnosis in up to 93% of patients.⁽¹⁴⁾ We have begun to use this approach only recently, and we believe it to be an excellent method for approaching mediastinal lesions. However, for accurate histopathological analysis, a sufficient volume of tissue must be obtained since differential diagnosis is very difficult, especially when tumors consisting of small non-differentiated cells are involved.⁽⁶⁾

Despite being quite common in adults, mediastinoscopy is not frequently used in children. The data show that mediastinoscopy is used in only 2% of infants with mediastinal tumors. ⁽¹⁾ The mediastinoscope is introduced through a suprasternal cross-incision and it is guided to the middle and inferior mediastinum, close to the anterior wall of the trachea. This method is used to reach the pretracheal and paratracheal regions of the mediastinum in the retrovascular plane.^(1,6)

We prefer the Chamberlain procedure since it is a safe and rapid procedure and does not result in high morbidity in children.⁽¹⁵⁾ We have made a small modification to the original technique: we do not remove the rib from the intercostal space used for the incision. If rib spreading does not allow adequate access to the lesion, we disconnect the rib from the sternum, thus widening the surgical field. At the end of the procedure, we reconnect the rib to the sternum with absorbable sutures. In 1999, Glick et al. related 16 cases, in which they performed 13 Chamberlain procedures and 6 mediastinoscopies. Diagnostic accuracy was 83% for mediastinoscopy and 100% for the Chamberlain procedure.⁽¹⁵⁾

We observed no surgical complications over the course of our study, despite the fact that such complications have been reported for the various surgical approaches to the mediastinum.^(1,6)

Mediastinal tumors are responsible for significant morbidity and mortality in children. Surgery plays an important role in the management of these tumors. In some types of tumors, such as posterior mediastinal tumors of neural origin, surgery plays a fundamental role in their treatment and resection. In cases of lymphoma in the anterior mediastinum, which respond very favorably to chemotherapy or radiation therapy, surgery is an important diagnostic tool.

References

Submitted: 22/01/2003. Accepted, after revision: 02/06/2003

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• 11. Fukai I, Masaoka A, Fujii Y. Thymic neuroendocrine tumor (thymic carcinoid): a clinicopathologic study in 15 patients. Ann Thorac Surg 1999;67:208-11.
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• 13. Inci I, Turgut M. Neurogenic tumors of the mediastinum in children. Childs Nerv Syst 1999;15:372-6.
• 14. Rodgers BM. Pediatric thoracoscopy: where have we come and what have we learned? Ann Thor Surg 1993;56:704-7.
• 15. Glick RD, Pearse IA, Saenz NC. Diagnosis of mediastinal masses in pediatric patients using mediastinoscopy and the Chamberlain procedure. J Pediatr Surg 1999;34:559-64.

*

Work performed in the Pediatric Thoracic Surgery Sector of the Department of Pediatric Surgery and Pediatric Oncology – Hospital de Clínicas de Porto Alegre, Faculdade de Medicina da Universidade Federal do Rio Grande do Sul, Porto Alegre – RS – Brasil.

Publication Dates

• Publication in this collection
  02 Mar 2004
• Date of issue
  Oct 2003

History

• Accepted
  02 June 2003
• Received
  22 Jan 2003