[Neurogenic tumors of the mediastinum in adults]

Low-Grade Malignant Peripheral Nerve Sheath Tumor: A Case Report of Exceptional Parapatellar Location in the Knee

Malignant tumors of the peripheral nerve sheaths are uncommon, constituting a small percentage, typically ranging from 2% to 5% of soft tissue sarcomas. Etiological diagnosis is often difficult but is guided by imaging and confirmed by histopathological and immunohistochemical examination. We report a case of a 46-year-old woman admitted for management of a mass in the medial parapatellar region of the right knee. Her medical history included a burn to the right leg five years ago and a previously undocumented resection of a medial parapatellar tissue mass in the right knee. Radiological examination showed a deep and superficial soft tissue mass in the medial soft tissue of the right knee opposite the patella, with no hemorrhagic components and heterogeneous enhancement after injection of gadolinium. Histopathology confirmed the diagnosis of a low-grade peripheral nerve sheath tumor, and a thoracic-abdominal-pelvic CT scan was performed, which was normal. Treatment consisted of a simple carcinological resection and local radiotherapy. No local recurrence was noted after one year of follow-up.

Complete anterior-posterior minimally invasive thoracoscopic robotic-assisted and posterior tubular approach for resection of thoracic dumbbell tumor

Thoracic dumbbell tumors are relatively uncommon neoplasms that arise from the neurogenic elements. Surgical resection can be challenging as the tumor involves both the spinal canal and thoracic cavity. Historically, thoracotomy and laminectomy were utilized for the resection of these tumors. Although single-stage removal of such tumors has been described recently, there is no prior description of a total minimally invasive single-stage resection of a thoracic dumbbell ganglioneuroma. The current report describes a completely minimally invasive surgical resection for such a tumor performed using the posterior minimally invasive tubular approach to resect the intraspinal component with ligation of the T2 nerve root in conjunction with robotic-assisted thoracoscopic resection of the extraforaminal, intrathoracic component of the tumor. This report illustrates the safety and utility of a completely minimally invasive endoscopic resection of a thoracic dumbbell tumor that can potentially obviate the morbidity associated with open surgical resections for such tumors.

Successful Management of Intrathoracic Phrenic Malignant Peripheral Nerve Sheath Tumor by Multimodal Treatment

Malignant peripheral nerve sheath tumors (MPNSTs) are rare and can be associated with type 1 neurofibromatosis. They are rarely located at the mediastinum, most often at the posterior mediastinal compartment or the paravertebral gutters. MPNSTs of the anterior mediastinum arising from the phrenic nerve are exceptional. Their prognosis is poor due to the high potential of local tumor recurrence and metastasis. Complete surgical resection remains the only radical treatment. However, the outcomes after this treatment alone cannot be considered satisfactory. Preoperative chemotherapy could be an interesting therapeutic option for unresectable tumors. We report here the case of a 77-year-old woman with an MPNST located at the anterior mediastinum arising from the phrenic nerve. This tumor was successfully managed with multimodal therapy combining preoperative chemotherapy, complete surgery and adjuvant radiation.

A single-institution experience of neurogenic tumors of the mediastinum

Background

Neurogenic tumors of the mediastinum are rare tumors located mainly in the posterior mediastinum. The aim of this study was to report a single-institution experience of these tumors.

Methods

This study was conducted between 2005 and 2017. Bivariate analysis was performed to assess correlations between the cellularity, mitotic index, presence of a capsule, and potential for malignancy of peripheral nerve sheath tumors.

Results

There were 86 patients enrolled in the study. The mean age was 42.51 years. Nineteen patients were asymptomatic and their tumors were discovered incidentally. Microscopic diagnosis confirmed a schwannoma in 45 cases, neurofibroma in 12, malignant peripheral nerve sheath tumor in 9, ganglioneuroma in 14, ganglioneuroblastoma in 4, and neuroblastoma in 2. Bivariate analysis showed a significant correlation between the absence of a capsule, the degree of atypia, a high mitotic index, and high cellularity with the potential for malignancy ( p < 0.05). Surgical resection was the main treatment modality in 84 cases. The mean survival was estimated to be 51.309 months. The log-rank test showed a significant difference in survival according to histologic subtype and between benign and malignant tumors ( p < 0.0001).

Conclusion

Even if radiologic means are helpful in suggesting the diagnosis, a positive diagnosis of neurogenic tumors is based on microscopic features. High mitotic activity and cellularity, and severe cytonuclear atypia are the features most suggestive of malignancy.

False Positive 18F-FDG Positron Emission Tomography Findings in Schwannoma-A Caution for Reporting Physicians

Schwannoma is a rare source of false-positive 18F-fluorodeoxyglucose (18F-FDG) uptake in Positron-emission tomography (PET/CT), inducing potential errors in staging of several solid cancer, with implications for patient management. This clinical case reports the situation of a patient undergoing an 18F-FDG-PET/CT for initial staging of an ovarian adenocarcinoma. We found a high paramediastinal hypermetabolic mass suspicious of remote extension or secondary synchronous primitive tumor. The biopsy finally reveals a histopathology of Schwannoma, allowing the patient to be eligible for a surgical procedure of her ovarian adenocarcinoma by rejecting the hypothesis of malignancy.

[Neurogenic mediastinal tumors in adults]

INTRODUCTION

Neurogenic mediastinal tumors are tumors develop at the expense of peripheral nerve elements of the mediastinum, the sympathetic nervous tissue and paraganglia. The series that we propose has the distinction of a high frequency of malignant forms and a wealth of clinical symptomatology.

METHODS

This is a retrospective study of 9 patients collected over a period of 6 years. The epidemiological aspect, clinical, radiological, surgical treatment and his results, histological diagnosis and prognosis were reviewed.

RESULTS

Five women and 4 men were identified. All patients were symptomatic at diagnosis. Tumor resection was complete in 8 cases. In 3 patients, there was a malignant tumor. Two of them had received chemo-radiotherapy. The others showed good clinical progress with a mean of 35 months.

CONCLUSION

Neurogenic tumors in adults are usually discovered incidentally. When the malignant forms predominate or in the presence of large tumor, the symptoms can be quite marked. In all cases the treatment based on a complete surgical resection remains the only guarantee of a good prognosis.

A large schwannoma of the middle mediastinum: A case report and review of the literature

Schwannoma of the mediastinum is a rare and typically benign type of tumor. The present study describes the case of a 61-year-old woman who presented with a continuous cough and facial edema. Pre-operative chest radiography, enhanced computed tomography (CT) and three-dimensional CT scans identified a well-circumscribed mass. The large cyst, measuring 6.5×6.1×5.0 cm, was located anterior to the trachea and posterior to the superior vena cava. The mass was observed to be in close proximity to the right pulmonary hilum and the superior vena cava was flattened due to the pressure on the right vagus nerve. Therefore, the encapsulated tumor was completely resected under thoracoscopy and was subsequently diagnosed as a benign schwannoma upon pathological examination. The respiratory tract symptoms and facial edema resolved immediately after the surgery, and no recurrence was observed during the 6-month follow-up period. At the time of writing, the patient remained alive. The present study records the rarely successful resection of a middle mediastinal tumor by video-assisted thoracoscopy.

[Malignant peripheral sheath nerve tumor: An exceptional mass of the anterior and middle mediastinum]

Malignant peripheral nerve sheath tumors (MPNST) are rare nervous tumors usually located in the posterior mediastinum in the paravertebral gutters. We report the case of a non-smoking 62-year-old man who was admitted with a 4 months history of cough, hoarseness and shortness of breath. Physical examination noted a superior vena cava syndrome. CT scan of the chest revealed a right anterior and middle mediastinal mass compressing the superior vena cava, the ascending aorta, the right pulmonary artery, invading the superior root of the pulmonary vein and the right auricle. Flexible bronchoscopy showed extrinsic compression of the right main bronchus, the right upper lobe bronchus and intermedius bronchus. The patient underwent surgical biopsy of the mass by mediastinoscopy. Histological examination revealed a malignant peripheral nerve sheath tumor. The patient received a single cycle of chemotherapy (ifosfamid-adriamycin). Clinical course was marked by the fast worsening of the dyspnea and the general state. Patient died three weeks after the cure of the chemotherapy. This case is original by the exceptional clinical presentation of MPSNT with a superior vena cava syndrome and the very rare location of this tumor in the anterior and middle mediastinum.

[Intrathoracic giant peripheral nerve sheath tumor during Von Recklinghausen disease]

We report the case of a patient aged 23, admitted for bilateral intrathoracic tumor, including a giant right. Surgery was performed by right sternothoracotomy. After 7 days, she presented an irreversible cardiac arrest. The malignant peripheral nerve sheath tumors are rare and aggressive. Their incidence is 0.001% in the general population and 0.16% in patients with neurofibromatosis type 1. These tumors are characterized by their risk of recurrence and poor prognosis. The treatment is the surgical resection. We analyze incidence, diagnosis and prognosis of these tumors.