Diagnosis and treatment of the giant malignant peripheral nerve sheath tumor in the anterior mediastinum: A case report

INTRODUCTION: Malignant peripheral nerve sheath tumor (MPNST) occurs in young and middle-aged people, more frequently in those with the genetic disease known as neurofibromatosis type 1 (NF1). Approximately, 50% of people with MPNST have NF1 and 13% of people with NF1 will get MPNST during their lifetime.

CASE REPORT: A 30-year-old patient after surgery for MPNST of the right hip in 2013 was observed. In 2017, a relapse was detected, and combined treatment was performed, including surgical excision of the relapse and postoperative distance radiotherapy with a total focal dose of 66 Gy. In 2018, MPNST of the left femoral nerve was diagnosed, and the tumor was excised. In 2020, a chest X-ray diagnosed a single focus of localized opacity in the anterior mediastinum, adjacent to the right lung. Computed tomography (CT) was performed to further verify the neoplasm, which revealed a single hypodense focus in the anterior mediastinum, adjacent to the right lung. According to histological examination of a tumor biopsy obtained by transthoracic ultrasound-guided biopsy, MPNST was verified. Magnetic resonance imaging (MRI) with intravenous contrast enhancement, including real-time MRI, was performed to assess the invasion of the mass into soft tissues and vessels and to plan surgical treatment. The following surgeries were done: right thoracotomy, removal of a neoplasm of the anterior mediastinum with resection of the upper lobe of the right lung, and marginal resections of the lower lobe of the right lung. This case demonstrates a rare localization and non-standard instrumental diagnosis of mediastinal MPNST. Apart from CT scanning, the patient underwent MRI of the thoracic organs. MRI allows assessing the invasion of the neoplasm into the surrounding tissues. This cannot always be achieved by CT scans, including those with contrast enhancement. Invasion is an important component in the planning of further surgical treatment tactics.

CONCLUSIONS: MPNST is a tumor with an aggressive course and a poor prognosis due to resistance to therapy. This clinical case demonstrates a rare localized MPNST with a recurrent course and metastases to the lungs. The current radiological methods, such as CT and MRI, may be used effectively both for diagnosing MPNST and determining the appropriate surgical access to the lesion and the extent of surgery.