Primary mediastinal tumors: part II. Tumors of the middle and posterior mediastinum

Foregut duplication cyst associated with esophageal atresia-one-stage neonatal surgical repair

Foregut duplication cysts can occur anywhere along the foregut-derived structures. Its association with esophageal atresia (EA) and tracheoesophageal fistula (TEF) is exceptionally rare, the majority of cases being diagnosed at an older age due to symptoms or complications. We present the third reported case in the literature, when diagnosis and treatment were done at the time of repair for EA-TEF.

Proposal for a new mediastinal compartment classification of transverse plane images according to the Japanese Association for Research on the Thymus (JART) General Rules for the Study of Mediastinal Tumors

There is no existing worldwide published method for mediastinum compartment classification based on transverse section images for the differential diagnosis of mediastinal tumors. Herein, we describe a new method for anatomic mediastinal compartment classification using transverse section computed tomography (CT) images and the use of this method to classify mediastinal lesions, and thus evaluate whether the method is sufficiently user-friendly and useful. In a publication of the Japanese Association for Research on the Thymus (JART), we proposed the following four mediastinal compartments based on transverse CT images: superior portion of mediastinum, anterior mediastinum (prevascular zone), middle mediastinum (peri-tracheoesophageal zone), and posterior mediastinum (paravertebral zone). In the present study, we retrospectively analyzed 445 pathologically proven mediastinal mass lesions, and categorized them into the proposed four compartments by consensus reading. Mass lesions were classified into compartments based on the location of the lesion centroid, and each lesion was satisfactorily categorized into a compartment. Almost all thymic epithelial tumors (99%, 244/246), all 24 thymic malignant lymphomas and a majority of germ cell neoplasms (93%, 54/58) were classified as being in the anterior mediastinum compartment. The majority of intrathoracic goiters (82%, 14/17) were categorized as being in the superior portion of the mediastinum compartment. Approximately two-thirds of mass lesions in the middle mediastinum were cysts, including foregut and pericardial cysts. Approximately 80% of 37 mass lesions in the posterior mediastinum were neurogenic tumors. Correspondingly, 29 of the 49 neurogenic tumors (60%) were categorized as being in the posterior mediastinum, while 10 (20%) were in the superior portion of the mediastinum, 4 (8%) in the anterior mediastinum, and 6 (12%) in the middle mediastinum. Our findings showed that the newly proposed mediastinal compartment classification using transverse images appears to be user-friendly enough for practical clinical application and may be helpful in differential diagnoses.

Additional value of dual-energy CT to differentiate between benign and malignant mediastinal tumors: an initial experience

OBJECTIVES

To investigate the feasibility of dual-energy computed tomography (DECT) in differentiating malignant from benign mediastinal tumors.

MATERIALS AND METHODS

We prospectively enrolled 25 patients (14 males; mean age: 56.7 years) who had suspected mediastinal tumors on chest radiography or non-contrast chest computed tomography (CT). All patients underwent a two-phase DECT using gemstone spectral imaging (GSI) mode (GE HD750). For the quantitative analysis, two investigators measured the following parameters of the tumors in the early and the delayed phases: CT attenuation value in Hounsfield units (HU) and iodine concentration (mg/ml). Pathological results were used for a final diagnosis. Statistical analyses were performed using the Fisher's exact test and the Mann-Whitney t-test.

RESULTS

10 patients (40%) had benign pathology, while 15 (60%) had malignant pathology. The iodine concentration measurements were significantly different between benign and malignant tumors both in the early phase (1.38 mg/ml vs. 2.41 mg/ml, p=0.001) and in the delayed phase (1.52 mg/ml vs. 2.84 mg/ml, p=0.001), while mean attenuation values were not significantly different in both phases (57.8 HU vs. 69.1 HU, p=0.067 and 67.4 HU vs. 78.4 HU, p=0.086, respectively).

CONCLUSIONS

Dual-energy CT using a quantitative analytic methodology can be used to differentiate between benign and malignant mediastinal tumors.

Benign pericardial schwannoma in a Chinese woman: a case report

Background

Intrathoracic schwannomas are most frequently located in the posterior mediastinum. A Chinese woman presented with a benign pericardial schwannoma in the pretracheal space and aortopulmonary window, a location which has not been described previously in the literature.

Case presentation

A 50-year-old Chinese woman initially reported a cough associated with a small amount of sputum. Contrast-enhanced computed tomography (CT) subsequently revealed a 9 × 11 cm² lobulated mass with sharp margins that presented as a capsule with heterogeneous enhancement and punctate calcification. Complete surgical resection was performed using a thoracotomy approach. The resected intrapericardial tumor was a firm, large mass with lobulation. Capsulation prevented infiltration of the mass into adjacent organs. Pathological examination verified that the tumor was a benign pericardial schwannoma.

Conclusion

This is the first reported case of a benign pericardial schwannoma located in the pretracheal space and aortopulmonary window. While a contrast-enhanced CT scan was able to differentiate this pericardial schwannoma from other middle mediastinal tumors, the exact diagnosis and plan for treatment depended on a pathological examination. For similar cases involving pericardial schwannomas, complete surgical resection is recommended, particularly for the prevention of life-threatening cardiopulmonary complications.

Giant neurogenic tumors of mediastinum: report of two cases and literature review

Neurogenic tumors are commonly found in the mediastinum, especially in the posterior mediastinum or in the chest wall, neurogenic tumors may reach large size before becoming symptomatic. If the neurogenic tumor occupied more than half size of the chest wall accompanied by mediastinal shift, tracheal compression, or superior vena reflux disorder, it may be called giant intrathoracic neurogenic tumors. Giant intrathoracic neurogenic tumors are relatively rare. Most of intrathoracic neurogenic tumors were benign or low-grade malignant tumors in nature. Complete surgical excision should be the rule for these patients. We report two cases of giant neurogenic tumors, and study the clinical manifestations, diagnostic methods, surgical management, and prognosis in the light of the most important published data.

Thymic neoplasm: a rare disease with a complex clinical presentation

Thymic neoplasms constitute a broad category of rare lesions with a wide spectrum of pathologic characteristics and clinical presentations which therefore require a high index of suspicion to diagnose. The natural history of the disease is seldom predictable, anywhere from an indolent to an aggressively malignant course. Although the classification and staging of these lesions are complex and controversial, complete radical surgical resection remains the gold standard of therapy. Radiation and chemotherapy are important elements of the multimodality approach to treating these patients and it is important for thoracic surgeons to work closely with their colleagues in other disciplines in the management of and future research endeavors in thymic neoplasm. In this review, we discuss the evaluation of the patient with an anterior mediastinal mass, the classification and staging of thymic neoplasms, the role of surgery, radiation and chemotherapy in treating this disease, as well as future directions in research for novel targeted therapies.

A case of posterior mediastinal ganglioneuroma: the importance of preoperative multiplanar radiological imaging

Ganglioneuromas are mostly seen in adolescents and young adults and they are neurogenic tumors originating from sympathetic ganglions with a benign histology. Although ganglioneuromas are benign, the treatment is surgical as they can cause pain or compression symptoms, can be locally aggressive and can lead to cord compression. We present a young adult female with a ganglioneuroma of the right posterior mediastinum who presented with lower back pain, together with the clinical features, Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) findings, differential diagnosis tips and their contribution to surgical planning.

Schwannoma in anterior mediastinum with massive pericardial effusion

Schwannoma is a benign nerve sheath neoplasm of schwann cell origin. Mediastinum is the second most common site of schwannoma with majority originating in the posterior medistinum. Mediastinal schwannoma is slow growing and mostly asymptomatic in presentation. We present a case of schwannoma arising in the anterior mediastinum, an unusual location, complicated by massive haemorrhagic pericardial effusion. We recommend an aggressive approach in such cases with pericardiectomy to prevent reaccumulation of the pericardial fluid.

Imaging of an atypical pericardial cyst

Pericardial cysts are uncommon mediastinal lesions that are usually congenital in origin. Patients are usually asymptomatic and the cysts are generally discovered on routine radiography for unrelated purposes. This case illustrates a symptomatic presentation of a haemorrhagic pericardial cyst in which radiographic, echocardiographic and multislice (MRI and CT) imaging were performed. The imaging findings were not typical of pericardial cysts leading to a diagnostic quandary despite the varied imaging techniques. In conclusion, it is important to appreciate that the imaging findings of pericardial cysts can be varied. Radiologists and clinicians alike should be aware of this variability.

Experience of video-assisted thoracoscopic resection for posterior mediastinal neurogenic tumours: a retrospective analysis of 58 patients

INTRODUCTION

The objective of this study was to review the experience of video-assisted thoracoscopic resection of posterior mediastinal neurogenic tumours and to investigate the technical features and difficulties of this thoracoscopic approach.

METHODS

From May 2001 to June 2011, 58 consecutive patients underwent thoracoscopic resection of posterior mediastinal tumours sequentially in our institution, including 36 males and 22 females. The median age of the patients was 38.7 years. The median tumour size was 4.9 cm. Twenty-four lesions were located at the left side, 33 lesions at the right side and 1 lesion at the bilateral side. All procedures generally required three ports, and intracapsular enucleation was preferred. For bulky tumours, dense adhesion and massive bleeding, conversion to thoracotomy was performed by extending the anterior incision to 6-10 cm.

RESULTS

All procedures were successfully performed without death or serious complications occurring. The average operating duration was 127.2 min. The average intraoperative blood loss was 206.4 mL. The average chest tube drainage duration was 2.72 days. The average post-operative stay was 5.19 days. Fifty-three procedures were performed entirely under thoracoscopy to achieve gross total resection. There were five cases (8.6%) of conversion to thoracotomy procedure. Seven patients suffered from post-operative complications, including four Horner syndromes. No local recurrence occurred after an average follow-up of 44.9 months.

CONCLUSION

Video-assisted thoracoscopic resections of the posterior mediastinal tumours were safe and reliable for selected patients with mastered thoracoscopic skills. Intracapsular enucleation was demonstrated to be a safe procedure. For tumours larger than 6 cm and located in the apex, the risk of the operation increased significantly.

Schwannoma of the pulmonary artery

Schwannoma (neurilemmoma) originating from the pulmonary artery has not before been described. A 65 year-old male presented with dyspnoea on exertion. CT scan was negative for pulmonary thromboembolism, but showed a well circumscribed, heterogeneous mass, 52 mm × 45 mm × 41 mm, straddling the left pulmonary artery and compressing the left atrium. The mass was found at surgery to be originating from the lateral wall of the left pulmonary artery. The tumour was completely resected, and the pulmonary artery reconstructed. The mass was found to be a benign schwannoma on histopathology.

Interpretation of plain chest roentgenogram

Plain chest roentgenogram remains the most commonly ordered screening test for pulmonary disorders. Its lower sensitivity demands greater accuracy in interpretation. This greater accuracy can be achieved by adhering to an optimal and organized approach to interpretation. It is important for clinicians not to misread an abnormal chest radiograph (CXR) as normal. Clinicians can only acquire the confidence in making this determination if they read hundreds of normal CXRs. An individual should follow the same systematic approach to reading CXRs each time. All clinicians must make a concerted effort to read plain CXRs themselves first without reading the radiologist report and then discuss the findings with their radiology colleagues. Looking at the lateral CXR may shed light on 15% of the lung that is hidden from view on the posteroanterior film. Comparing prior films with the recent films is mandatory, when available, to confirm and/or extend differential diagnosis. This article outlines one of the many systematic approaches to interpreting CXRs and highlights the lesions that are commonly missed. A brief description of the limitations of CXR is also included.

MRI findings of mediastinal neurogenic tumors

OBJECTIVE

The objective of this article is to review the clinical, pathologic, and MRI findings of mediastinal neurogenic tumors according to the three tumor origins: the peripheral nerves, sympathetic ganglia, and paraganglia.

CONCLUSION

MRI findings reflect pathologic features of mediastinal neurogenic tumors. Integrating consideration of age and clinical findings of the patient, lesion location, and imaging findings is important in the diagnosis of mediastinal neurogenic tumors.

Neuroendocrine tumor presenting like lymphoma: a case report

Introduction

Neuroendocrine tumors are a rare but diverse group of malignancies that arise in a wide range of organ systems, including the mediastinum. Differential diagnosis includes other masses arising in the middle mediastinum such as lymphoma, pericardial, bronchogenic and enteric cysts, metastatic tumors, xanthogranuloma, systemic granuloma, diaphragmatic hernia, meningocele and paravertebral abscess.

Case presentation

We present a case of 42-year-old Caucasian man with a neuroendocrine tumor of the middle-posterior mediastinum and liver metastases, which resembled a lymphoma on magnetic resonance imaging.

Conclusion

The differential diagnosis in patients with mediastinal masses and liver lesions should include neuroendocrine tumor.

Giant Posterior Mediastinal Ancient Schwannoma Requiring Thoracoabdominal Resection: A Case Report and Literature Review

Posterior mediastinal schwannomas are benign, slow growing nerve sheath tumors and rarely cause symptoms. We present a case of a 47-year-old man who presents with severe mid-back pain and dyspnea on exertion. Chest radiograph and computed topography revealed a large posterior mediastinum mass. Surgical resection required en bloc resection of a portion of the diaphragm, and wedge resection of the left lower lobe of the lung via left thoracoabdominal approach. Pathology was consistent with ancient schwannoma. This case is unique due to the location and size of the mass and the surgical approach required for complete resection.

Mediastinal schwannoma diagnosed by endoscopic ultrasonography-guided fine needle aspiration cytology

Schwannoma is the most common neurogenic tumor that is derived from the peripheral nerve sheath. There are no specific serologic markers or characteristic imaging abnormalities associated with schwannoma. Tissue diagnosis and immunohistochemistry are required to diagnose this lesion. We describe a 65-year-old male with a finding of three mass lesions in the superior and middle mediastinum on computed tomography of the chest. The largest lesion measured 4.6 × 5 cm. The patient subsequently underwent endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) of the lesion and cytology was consistent with spindle cell neoplasm. Immunohistochemical staining of the cytologic specimen was positive for S-100 and negative for pan-cytokeratin, CD34, CD117, calcitonin, smooth muscle actin and desmin. These findings were consistent with schwannoma. This is the second reported case of a mediastinal schwannoma diagnosed by EUS-FNA.

T cell lymphoma presenting as esophageal obstruction and bronchoesophageal fistula

BACKGROUND

The mediastinum is an uncommon location for presentation of peripheral T cell lymphoma. Esophageal involvement by non-Hodgkin's lymphoma is extremely unusual. Although staging can be performed with routine imaging studies, surgical intervention is often required to ensure accurate histologic diagnosis of these lymphomas. Peripheral T cell lymphomas not otherwise specified are among the most aggressive non-Hodgkin lymphomas with often a poor response to conventional chemotherapy.

CASE REPORT

We report a case of a 63 year-old-man with an aggressive mediastinal T cell lymphoma presenting as esophageal obstruction and bronchoesophageal fistula. The patient was treated with a cyclophosphamide, vincristine, and prednisone (COP) regimen. Repeat computer tomography scan of the chest after chemotherapy noted a significant decrease in the cavitary lesion in the right paraesophageal region and right mediastinum. Bronchoscopy revealed a large opening in the posterior wall of the bronchus intermedius leading into the esophagus. A fistulogram was done which clearly demonstrated a fistulous tract between the lower esophagus and the right intermediate bronchus secondary to perforation from the lymphoma. The patient eventually underwent cervical esophagostomy and jejunostomy tube placement to correct the brochoesophageal fistula.

CONCLUSIONS

The mediastinum is an uncommon location for presentation of peripheral T cell lymphomas, and surgical intervention is often required to ensure accurate histological diagnosis of these lymphomas. In our patient, aggressive mediastinal T cell lymphoma presented as esophageal obstruction and bronchoesophageal fistula.

Multiple schwannomas of the bilateral mediastinal vagus nerves

Multiple schwannomas arising from the mediastinal vagus nerve are very rare, but herein we report a case with such lesions involving the bilateral intrathoracic vagus nerves. A 43-year-old man presented with multiple mediastinal tumors during a check-up. A chest computed tomographic scan revealed multiple lesions that appeared strung together like beads along the right vagus nerve. Three small tumors were also evident on the left side of the esophagus. We performed a complete resection of the bilateral mediastinal tumors through right thoracoscopic surgery. The pathologic diagnosis for each of these tumors was a schwannoma without malignant components.

Anterior mediastinal mass: a rare presentation of tuberculosis

We report a case of a 14-year-boy who presented to us with a low-grade fever with evening rise for 9 months. Along with this, the patient also reported a reduction in his appetite and body weight. He had a mild dry cough but no respiratory symptoms otherwise. There was no other localization for fever on history. He received antitubercular therapy, based on abnormal chest radiograph. However, there was no relief in his symptoms. General physical examination revealed mild fever. Systemic examination was unremarkable. Blood investigations done for fever were noncontributory. Computed tomographic (CT) scan of the chest revealed a mediastinal mass compressing the trachea. The possibilities of lymphoma or germ cell tumour were considered. A biopsy from the mass under CT guidance was performed. The histopathology revealed multiple epithelioid cell granulomas with necrosis, and the diagnosis of tuberculosis was made. The clinical course of this patient and the relevant literature is presented in this paper.

Benign giant mediastinal schwannoma presenting as cardiac tamponade in a woman: a case report

Introduction

Mediastinal schwannomas are typically benign and asymptomatic, and generally present no immediate risks. We encountered a rare case of a giant benign posterior mediastinal schwannoma, complicated by life-threatening cardiac tamponade.

Case presentation

We report the case of a 72-year-old Japanese woman, who presented with cardiogenic shock. Computed tomography of the chest revealed a posterior mediastinal mass 150 cm in diameter, with pericardial effusion. The cardiac tamponade was treated with prompt pericardial fluid drainage. A biopsy was taken from the mass, and after histological examination, it was diagnosed as a benign schwannoma, a well-encapsulated non-infiltrating tumor, originating from the intrathoracic vagus nerve. It was successfully excised, restoring normal cardiac function.

Conclusion

Our case suggests that giant mediastinal schwannomas, although generally benign and asymptomatic, should be excised upon discovery to prevent the development of life-threatening cardiopulmonary complications.

[Primary mediastinal sarcomas]

INTRODUCTION

Primary sarcomas of the mediastinum are rare and account for 2 to 8% of malignant mediastinal tumours. The aim of this study is to describe their clinical and pathological characteristics.

PATIENTS AND METHODS

Fifteen cases of primary mediastinal sarcoma, diagnosed between 1993 and 2009, were reviewed retrospectively, noting the clinical, radiological and pathological findings, and the treatment given.

RESULTS

The patient population consisted of eight females and seven males with mean age of 40 years (14 to 73 years). The symptomatology was predominately respiratory. Imaging showed a mediastinal mass invading adjacent organs in nine cases. The diagnosis was made in all cases by histological examination. These 15 mediastinal sarcoma comprised 12 malignant peripheral nerve tumours, two liposarcomas and one angiosarcoma. Three were grade III, six grade II and six grade I. Ten were treated surgically, of which seven had radical resections. Associated treatments were neoadjuvant (one case) or adjuvant (one case) chemotherapy and postoperative radiotherapy (five cases). Radiotherapy was undertaken alone in three inoperable tumours. Eight patients (53%) had died.

CONCLUSION

Management of primary mediastinal sarcoma needs a multidisciplinary approach, and is based mainly on radical resection. The prognosis is poor and depends mainly on surgical excision and histological grade.

[Malignant peripheral nerve sheath tumors: A case report]

Malignant peripheral nerve sheath tumors comprehend a rare group of soft tissue sarcomas that tend to occur in patients with neurofibromatosis type 1 or several years after radiotherapy treatments. Its thoracic localization is a very unusual entity. The typical symptoms are due to nerve roots compression which can persist for several months or years before diagnosis. Due to very few patients with this type of tumor its therapeutic approach is still a matter of permanent debate, being surgery the main treatment. This tumor has a bad prognosis because of high local recurrence and metastasis. The clinical case we describe serves as a glimpse for discussion.

An uncommon cause of hiccups: sarcoidosis presenting solely as hiccups

Common causes of hiccups are over-distension of the stomach, a sudden change in gastrointestinal temperature, excessive alcohol and tobacco ingestion, and sudden excitement or emotional changes. Common presenting symptoms of sarcoidosis include cough, dyspnea, and chest pain. It is very rare for a sarcoidosis patient to present with hiccups. A 48-year-old man presented with hiccups of 2 weeks' duration. He denied having headaches, earache, cough, abdominal pain, fever, or body weight loss history. On physical examination, he had no peripheral lymphadenopathies in the neck, axilla and inguinal regions, no organomegaly in the abdomen and no skin abnormalities. A neurological examination showed normal findings. Laboratory investigations revealed a normal complete blood count, liver function, renal function, serum calcium, and tumor markers. Transabdominal ultrasound was negative, and panendoscopy revealed a small healing duodenal ulcer. Chest radiography showed an enlarged right lung hilum, while computed tomography showed enlargement of multiple mediastinal lymph nodes. Endoscopic ultrasound-guided fine-needle aspiration with a 22-gauge needle and trucut biopsy with a 19-gauge needle (quick-core biopsy needle) were performed, and cytology, cell block and histology revealed non-caseating granuloma, with negative tuberculous and fungus cultures. Mediastinal lymph node due to sarcoidosis can be a rare cause of hiccups.

Tumors of the mediastinum and chest wall

Primary tumors of the mediastinum and chest wall comprise a diverse group of conditions with a wide range of presentations. A thorough knowledge of thoracic anatomy is essential for appropriate diagnosis and treatment. Given their proximity to critical structures, treatment of these tumors is often challenging. Although surgery is the mainstay of therapy for most mediastinal and chest wall tumors, a multidisciplinary approach is valuable in many cases.

Thoracic neuroblastic tumors in childhood

AIM

Thoracic neuroblastic tumors (NBTs) are reported to have better prognosis. We aimed to review clinical characteristics, treatment results, and outcome of our patients with thoracic NBT.

PATIENTS AND METHODS

Files of 87 children treated at our hospital between 1973 and 2007 with the diagnoses of thoracic NBT were reviewed for clinical and pathological characteristics. Treatment results and outcomes of these cases were examined.

RESULTS

All but one tumors were located in posterior mediastinum, one in the posterior chest wall. Median age of all was 2.1 years (range, 0.03-14; F/M: 1.42). Fifteen cases had ganglioneuromas (GN), 26 ganglioneuroblastomas (GNBL), and 46 neuroblastomas (NBLs). Stages were: I, 20.5%; II, 22.1%; III, 38.2%; IV, 14.7%; IVS, 4.5%. Stages III and IV were more common in cases over 1 year of age. In 20 patients diagnoses were incidental. Twenty-two of 87 (25.3%) had symptomatic spinal cord compression and 15 (17.3%) had Horner syndrome. Ten-year overall and event-free survival rates were 71.2% and 67.4%, respectively. Survival rates did not differ depending on the age being younger or older than 1 year. Ten-year survival rates were 88.8% in stages I, II, IVS; 65.3% in stage III and 27.8% in stage IV (P = 0.0002).

CONCLUSIONS

Thoracic NBLs had a favorable prognosis. This might be a result of earlier diagnosis and some distinct biological characteristics. Favorable prognosis would suggest less aggressive treatment for such patients. Further studies on the biological characteristics of NBLs in the thoracic site and their association with outcome should be done.

[Mediastinal tumors: introduction]

Mediastinal tumors are relatively uncommon, usually incidentally discovered on a chest X-ray in asymptomatic patients. Young adults are particularly concerned. Mediastinal masses represent a group of heterogeneous histological type cell. A definite diagnosis is essential leading to an adequate prompt therapeutic strategy when either benign disease or aggressive malignant tumor is conceivable. Indeed the therapeutic management of such tumors could be strictly medical, requiring exclusive surgical approach or includes a multimodal treatment. Clinical examination and imaging are important tools in the diagnostic approach. However the specific diagnosis could be complex and requires histological confirmation by an experienced pathologist after examination of large biopsies of the tumor. Several investigations, including surgical invasive exploration, should be quickly requested in order to achieve a final diagnosis and refer patients in an adequate therapeutic scheme without delay. The aim of this article is to point out the available diagnostic tools in mediastinal masses, including surgical approach, and to identify the role of surgical resection in specific subtypes.

[Neurogenic tumors of the mediastinum in adults]

In adults, mediastinal neurogenic tumours constitute the third group of mediastinal tumours, after thymomas and lymphomas. If the group of neurogenic tumour is frequent, each type of tumour is relatively unusual in everyday's clinic. Among them, nerve sheath tumours are the more frequent, followed by tumour of the autonomic system. Askin tumour remains uncommon. Treatment of this tumour requires complete preoperative work-up, including standard radiography, CT-scan, MRI, and sometimes nuclear imaging. In most cases, the treatment is based on surgical resection, and may be associated with radiotherapy or chemotherapy in case of malignant tumour or incomplete resection. Better understanding of these tumours, including their molecular abnormalities, may lead to new changes in their classifications, and to their management.

Schwannoma of the vagus nerve, a rare middle mediastinal neurogenic tumor: case report

Schwannoma originating from the vagus nerve within the mediastinum is a rare, usually benign tumor. A 44-year old male was presented with chest pain. Chest radiography, CT scan and MRI showed a well circumscribed mass, 5 × 4 cm located in the aortopulmonary window. The mass was found at surgery to be in close proximity with the aortic arch and the left pulmonary hilum, alongside the left vagus nerve. The encapsulated tumor was completely resected through a left thoracotomy incision and it was found to be a benign schwannoma in pathology. The patient is free of recurrence 6 years after surgery.

Radiology-pathology conference: incidental posterior mediastinal ganglioneuroma

We report the radiology and pathology findings on a patient with an incidental posterior mediastinal ganglioneuroma and review the literature on this uncommon tumor.

Assessment of mediastinal tumors with diffusion-weighted single-shot echo-planar MRI

PURPOSE

To assess the role of diffusion-weighted single-shot echo-planar magnetic resonance imaging (MRI) in patients with mediastinal tumors.

METHODS

Prospective study was conducted on 45 consecutive patients (29 male, 16 female, age 22-66 years, mean 41 years) with mediastinal tumor. They underwent diffusion-weighted single-shot echo-planar MRI of the mediastinum with a b-factor of 0, 300, and 600 sec/mm(2). The apparent diffusion coefficient (ADC) value of the mediastinal tumor was correlated with the histopathological findings.

RESULTS

The mean ADC value of malignant mediastinal tumors was 1.09 +/- 0.25 x 10(-3) mm(2)/sec, and of benign tumors was 2.38 +/- 0.56 x 10(-3) mm(2)/sec. There was a significant difference in the mean ADC value between malignant and benign tumors (P = 0.001) and within different grades of malignancy (0.001). When an ADC value of 1.56 x 10(-3) mm(2)/sec was used as a threshold value for differentiating malignant from benign tumor, the best results were obtained with an accuracy of 95%, sensitivity of 96%, specificity of 94%, positive predictive value of 94%, negative predictive value of 96%, and area under the curve of 0.938.

CONCLUSION

The ADC value is a noninvasive parameter that can be used for differentiation of malignant from benign mediastinal tumors and grading of mediastinal malignancy.

Retroperitoneal ganglioneuroma in childhood--a presentation of two cases

Ganglioneuromas are considered to be part of the neuroblastoma series of tumors, which evolve from the sympathogonia of neural crest origin. As imaging techniques have become more widely practiced, the number of ganglioneuromas detected incidentally has increased. Preoperative diagnosis of retroperitoneal ganglioneuromas is often difficult and the diagnosis is usually based on histopathological findings after surgical excision of the tumor. We present two cases of this unique disease entity and discuss its clinical presentation, therapeutic approach, and clinical outcome.

Soft tissue Rosai-Dorfman disease of the posterior mediastinum

Rosai-Dorfman disease (RDD) consists of sinus histiocytosis with massive lymphadenopathy. Extranodal involvement occurs in up to 43% of cases. However, isolated soft tissue RDD is rare. Isolated mediastinal RDD is exceedingly rare, and there have been only three previous reports. Involvement of the posterior mediastinum in RDD has been reported only in the context of disseminated RDD. Here, we report the case of a 49-year-old female patient with a two-year history of cervical pain and lymphadenomegaly, which resolved spontaneously. A CT scan revealed a left paravertebral mass with a diameter of 6 cm. The patient was submitted to surgical excision of the mass. Microscopic examination and immunophenotyping of the surgical specimen led to a diagnosis of RDD. During a 12-month follow-up period, the patient complained of mild cough and chest pain. Periodic imaging tests showed no sign of recurrence, and no postoperative cervical lymphadenomegaly was detected.

Sonographic management of mediastinal syndrome

INTRODUCTION

Mediastinal syndrome is suspected on the basis of clinical symptoms and is generally confirmed by chest radiography or computed tomography (CT). However, also grey scale ultrasound (US) and contrast enhanced US (CEUS) are useful in this hematologic emergency as they provide the possibility to perform US-guided biopsy and histological diagnosis.

MATERIALS AND METHODS

15 Patients affected by mediastinal syndrome were prospectively studied using B-mode US and CEUS; 13 of these patients, who had no other lesions, were proposed for US-guided biopsy of the mediastinal mass, but only in 12 patients biopsy was technically possible.

RESULTS

In this study, B-mode US reached an excellent sensitivity (100%) in evidencing the lesions but a low specificity which did not exceed 30-40%. CEUS reached an elevated specificity identifying neoplastic pathologies if both the early and the late phases are considered (90-86.6%). US-guided biopsy was possible in 92.3% of lesions showing a diagnostic adequacy of 91.66%.

CONCLUSIONS

B-mode US associated with CEUS and US-guided biopsy reached an elevated accuracy in the diagnosis of mediastinal masses. If these results are confirmed by further studies, this diagnostic procedure could be included in the routine management of mediastinal syndrome.

Genetic markers of mediastinal tumors

Determination of the genetic markers by the application of new genomic methodologies has provided important insight into the pathogenesis of mediastinal disease. These new techniques have enabled scientists to uncover differential gene expression patterns between subtypes of thymomas, correlate tumor marker expression with germ cell tumors, and determine a link between the NF-kappaB and JAK/STAT pathways with Hodgkin's and non-Hodgkin's lymphoma. Despite the progress made in the understanding of genetic markers of select mediastinal tumors, significantly more investigation is required to elucidate the molecular pathways involved in the pathogenesis of these tumors.

[Computerized tomography of mediastinal tumors]

Tumors of the mediastinum represent a very heterogeneous group of primary and metastatic tumors. Most tumors of the mediastinum are detected on chest radiography, but for more precise view additional imaging methods are necessary. The most common causes of tumor mass in anterior mediastinum are thymoma, germ cell tumors, retrosternal goitre and Hodgkin's lymphoma. In the middle mediastinum most commonly tumors are congenital cysts, such as bronhogenic and pericardial cysts, and enlarged lymph nodes, while in the posterior mediastinum dominantly present neurogenic tumors. Complex anatomy of mediastinum infrequently makes difficulties in radiological diagnosis of these tumors. Computerized tomography (CT) is a radiological method of choice in the diagnosis of primary and/or secondary mediastinal lesions. Localization and structure of the tumor masses are very important for diagnosis. Knowledge of anatomy, with the standard topographic divisions on the anterior, middle and posterior mediastinum is necessary prerequisite for a valid CT diagnostic. Lesions in all parts of the mediastinum are systematically presented from the aspect of practical recommendations, with a view of the typical pathological findings.