Asian Cardiovasc Thorac Ann 2006;14:102-104
© 2006 Asia Publishing EXchange Ltd
Mediastinal Tumors: a Clinicopathological Analysis
Chandra P Shrivastava, MCh,
Sanjeev Devgarha, MCh,
Vikas Ahlawat, MCh
Department of Cardiothoracic & Vascular Surgery, SMS Medical College & Hospital, Jaipur, India
For reprint information contact: Chandra P Shrivastava, MCh Tel: 91 141 237 7329 Fax: 91 141 260 9988 Email: cps_sms{at}hotmail.com, H-16, Chitranjan Marg, C-Scheme, Jaipur (Raj.), India.
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ABSTRACT
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Between January 1993 and June 2003, 106 patients underwent surgical treatment of a mediastinal mass. Ages ranged from 6 months to 62 years, with peak incidence in the third and fourth decade of life (56%). The male to female ratio was 1.9:1. The anterosuperior mediastinum was involved in 76 patients (72%), middle mediastinum in 13 (12%), and posterior mediastinum in 17 (16%). Myasthenia gravis was present in 27% of cases. Complete surgical excision was possible in 68% of patients. Histopathologically, 41 (39%) patients had thymic pathology, 31 (29%) had lymphoma, 14 (13%) had germ cell tumors, 12 (11%) had neurofibroma, 4 (4%) had ganglioneuroma, 2 (2%) had bronchogenic cyst, and 1 each had thymic cyst and mesothelioma. The overall mortality was 3.8%.
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INTRODUCTION
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Mediastinal masses are relatively uncommon lesions that sometimes pose an interesting diagnostic and therapeutic problem for the clinician. The mediastinum is the extrapleural space bounded to the right and left by the pleural cavities, superiorly by the thoracic inlet, and inferiorly by the diaphragm. The anatomical subdivisions are the anterosuperior, middle, and posterior (includes costovertebral sulci) mediastinum. This retrospective study was performed to analyze the epidemiologic profile, clinical features, operative and histopathological findings in patients presenting with a mediastinal mass.
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PATIENTS AND METHODS
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Patients with a mass arising primarily in the mediastinum, who were operated on between January 1993 and June 2003, were included in the study. Those with esophageal, pulmonary, or metastatic tumors were excluded. Of 106 patients, 70 were male and 36 were female, the male to female ratio was 1.9:1. The age range was 6 months to 62 years. The majority (51%) were in the third and fourth decades of life (Table 1
). Presentation was dependent on the location, size, invasiveness, degree of compression, and endocrine effects of the tumor. Presenting features included dyspnea, cough, chest pain, hoarseness of voice, weight loss, and features suggestive of myasthenia gravis. The anatomical location of the mediastinal mass was determined by chest radiographs (posteroanterior and lateral views). Computed tomography was performed to assess operability. Neurologic evaluation was carried out in cases of suspected myasthenia gravis. The surgical approach was according to the anatomical location of the tumor. Excised mediastinal masses were evaluated histopathologically and treated accordingly.
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RESULTS
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The majority of patients presented with chest pain and weight loss (Table 2). The surgical approach was decided on the basis of the anatomical location of the tumor. Most patients underwent a thoracotomy, but a combined median sternotomy and anterolateral thoracotomy had to be performed in 2 patients because of massive tumor size (Table 3). Complete excision was carried out in 72 (68%) patients, whereas only biopsy and debulking was possible in 34 (32%). Benign lesions were found in 65 (61%) patients, 41 (39%) had a malignant mediastinal mass. The histopathological diagnosis and sites of the tumors are listed in Table 4. Thymic neoplasms were the most common anterosuperior mediastinal lesion (54%). Benign noninvasive thymic tumors were sharply delineated, well encapsulated, and solid or cystic in consistency. Seven thymic tumors were found to infiltrate the surrounding tissues; radical thymectomy (whole of the mediastinal fat, pericardium, and pleural tissues) was undertaken in 5 cases, whereas only debulking was possible in 2. Lymphomas were the second most common lesion; there were 26 cases of Hodgkin’s lymphoma and 5 of non-Hodgkin’s. The germ cell tumors in all 14 patients were in the anterior mediastinum. These were small thin-walled cysts or large solid tumors. Plain chest radiographs showed evidence of calcification in 36% of patients. Neurogenic tumors comprised 7 neurilemomas, 5 neurofibromas, and 4 ganglioneuromas. All were in the posterior mediastinum except for one neurilemoma in the anterosuperior mediastinum. There were 2 patients with a dumbbell tumor that was successfully removed by combined posterolateral thoracotomy and laminectomy. Both were males, aged 13 and 32 years.
Four patients died: one due to thymic crisis leading to prolonged ventilation and subsequent septicemia, one due to advanced malignancy, one had malignant thymoma and developed an unstable sternum postoperatively with associated infection, and one died because of excessive bleeding. The overall mortality was 3.8%.
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DISCUSSION
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Since the causes of mediastinal neoplasms are diverse, true incidence data are lacking. A study of mediastinal masses in the black African population comprised 75 males and 30 females, with a mean age of 34 ± 20.4 years.1 Most patients with a mediastinal mass (whether benign or malignant) were symptomatic; absence of symptoms was most often associated with benign disease.1 Only 3 patients in this series were asymptomatic. As found in this study, thymic neoplasm is the most common lesion in the anterosuperior mediastinum.2–4 Among all mediastinal masses, neurogenic tumors are the most common.2,3 The majority of lesions are reported to be situated in the anterosuperior mediastinum (63.8%), with lymphoma being the most common (21.9%).1 This is also in agreement with the findings in this study.
A study of carcinoid tumors of the thymus revealed that most patients had symptoms, but approximately one third were asymptomatic.5 All cases were treated by surgical excision. The tumors displayed a variegated histologic appearance and unusual cytologic features. Some cases showed transition from low to high grade within the same tumor mass.5 In this series, two patients had carcinoid tumor of the thymus with symptoms of chest pain and weight loss. Primary non-Hodgkin’s non-lymphoblastic lymphoma most often occurs in young adults and has an aggressive clinical course. Observations have also suggested that intensive chemotherapy and bone marrow transplantation are needed for patients who relapse or fail to gain complete remission.6 In this study, 5 patients had non-Hodgkin’s lymphoma and postoperative chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone was given.
Teratomas in the mediastinum arise from pluripotent cells and are composed of a wide diversity of tissues originating from three germ layers: ectoderm, mesoderm, and endoderm. Benign teratomas are usually slow growing, cause minimal symptoms, and are often discovered on a routine chest radiograph. They are well circumscribed and can usually be removed without much difficulty. Malignant teratomas are fast growing, diffuse, and often cause pressure symptoms early.7 In this series, 14 patients had germ cell tumors. Multimodality treatment including surgery, radiotherapy, and cisplatin-based combination chemotherapy gives the most satisfactory results in the treatment of malignant mediastinal germ cell tumors.8 Multimodality treatment was given to all 14 patients in this series, with satisfactory results. A review of 56 cases of primary malignant germ cell tumors of the mediastinum revealed that these tumors occurred in young adults (mean age, 29 years) but the sex distribution differed (86% male and 14% female).9 A single germ cell element was found in 37 (66%) of the tumors, and various combinations were present in the remaining 19 (34%).9 Complete excision was possible in 68% of cases. The incidence of malignancy in this series was 39%, which is slightly higher than that reported by others (range, 25% – 35%), probably due to ours being a referral center.2–4 Primary thymic carcinoma is a rare malignant neoplasm that arises from the thymic epithelium. One report noted that the most common presenting symptoms were chest pain, cough, weight loss, and dyspnea.10 In this series, 7 patients had thymic carcinoma, 5 underwent radical thymectomy, and debulking was performed in 2.
The limitations of various diagnostic methods suggest that exploratory thoracotomy can be used for taking a biopsy and establishing the diagnosis in inoperable cases of mediastinal mass. If found to be operable, excision can be performed through the same approach. As demonstrated in this study, this can be accomplished with low morbidity and mortality.
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REFERENCES
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ABSTRACT
INTRODUCTION
