Rare Condition of Intrathoracic Phrenic Nerve Schwannoma Successfully Treated with Uniportal Video-Assisted Thoracoscopic Surgery

Introduction. Neurogenic tumors in the mediastinum account for approximately 20-30% of all types of mediastinal tumors in adults. This pathology is usually benign and has no or very few symptoms. Schwannoma rarely involves the phrenic nerve. We report a unique case of schwannoma involvement of phrenic nerve. Case Presentation. The 43-year-old female patient has an annual check-up of computerized tomography to detect the mass in the right middle mediastinum, so the patient was admitted to the hospital. Chest computerized tomography image found a mass of the middle mediastinum with the size of 23 × 22.3 mm located between the right pulmonary artery and the pericardium with uniform margins and clear boundaries, not invading the surrounding organization. Very little contrast is absorbed after injection. She underwent a uniportal video-assisted thoracoscopic surgery, and this mass was found to be originating from the right phrenic nerve. Resection of the portion of phrenic nerve with mass was performed. Postoperatively, the patient was discharged from the hospital after 4 days of treatment in a clinical condition with no difficulty breathing and no chest pain; postoperative X-ray showed no abnormality, and the right diaphragm was unchanged. Conclusion. Although they are very rare, schwannomas of the phrenic nerve should be considered in the differential diagnosis of mediastinal tumors. Uniportal video-assisted thoracoscopic surgery is a preeminent option with properly sized tumors that deliver good results and have no postoperative complications associated with surgery.

An ectopic thymoma arising in the middle mediastinum that was difficult to distinguish from a lymph node metastasis

Background Ectopic thymomas often occur in the upper mediastinum; however, they rarely arise in the middle mediastinum, especially on the dorsal side of the innominate vein and superior vena cava in the peribronchial region. Case presentation Six years prior, a 27-year-old female presented to our department and was diagnosed with locally advanced left breast cancer. First, we administered chemotherapy including an anti-human epidermal growth factor receptor 2 antibody. The size of the tumor was markedly reduced, and a radical operation involving mastectomy and axillary lymph node dissection was then performed. The patient underwent radiotherapy after the mastectomy, followed by trastuzumab therapy; she continued to receive endocrine therapy thereafter. She underwent computed tomography once a year after the surgery, and a nodule in the middle mediastinum on the dorsal side of the innominate vein and superior vena cava in the parabronchial region was detected at 4 years. We speculated that the nodule was a solitary mediastinal lymph node metastasis from her breast cancer; therefore, we performed thoracoscopic resection of the tumor. We diagnosed the tumor as a thymoma. Currently, the patient visits our hospital to receive continuous hormone therapy for her breast cancer, and the latest computed tomography scan demonstrated no metastases from or recurrence of her breast cancer or thymoma. Conclusions We report a case of ectopic thymoma in the middle mediastinum. The tumor, which was detected during systemic therapy for locally advanced breast cancer, was located on the dorsal side of the innominate vein and superior vena cava in the parabronchial region and was indistinguishable from a lymph node metastasis from breast cancer.

Surgical resection of a middle mediastinal paraganglioma that caused diabetes

Background Paragangliomas are rare neuroendocrine tumors originating from chromaffin cells of extra-adrenal origin. Ninety percent of adrenergic tumors originate in the adrenal medulla and are known as pheochromocytomas; the remaining 10% are extra-adrenal and are called paragangliomas. Mediastinum paragangliomas is rare and commonly originate from the posterior mediastinum, while those originating from the middle posterior are quite rare. Some paragangliomas secrete catecholamines, leading to symptoms such as hypertension, tachycardia, and diabetes. Case presentation A 76-year-old woman visited our hospital for the treatment and further evaluation of diabetes. Her hemoglobin A1c levels had risen to 11.0%. To investigate the cause of her diabetes, a contrast-enhanced chest computed tomography scan was performed, revealing a ring-enhancing tumor (30 × 30 mm) in the middle mediastinum. The surgical resection was performed via video-assisted thoracic surgery. Surgery was performed using a vessel-sealing device; however, bleeding was persistent from the surrounding tissue. Total bleeding was 400 g. Blood pressure fluctuations and arrhythmia did not occur during the operation. The patient’s uncontrolled diabetes was cured after the surgery, and the tumor was diagnosed as a functional paraganglioma. Conclusions We encountered a rare case of functional paraganglioma located in the middle mediastinum. Functional paragangliomas should be considered as a potential cause of uncontrolled diabetes, and a whole-body CT scan should be performed to investigate this possible cause.

Mediastinal tumours and cysts

Mediastinal masses are most conveniently categorized by their anatomical site in the anterior, middle, or posterior mediastinum. Most present as a radiographic abnormality alone, or in association with symptoms arising from compression of other mediastinal structures. Systemic symptoms such as fever or weight loss are more likely with malignant tumours such as lymphomas or thymomas. Detailed knowledge of normal mediastinal anatomy is a prerequisite to the interpretation of both normal and abnormal chest radiographs. Lymph nodes are present in all three compartments thereby knowledge of their anatomical relationships, together with sites of drainage, is important when interpreting radiographic mediastinal enlargement. The most important group of visceral nodes lie in the middle mediastinum and are predominantly subcarinal and paratracheal. Bronchopulmonary and hilar nodes are numerous but not visible radiographically unless pathologically enlarged.