A Large Intrathoracic Mass in A Patient With Neurofibromatosis Type 1

Dural ectasia is circumferential extension or dilatation of the dural sac, it is commonly associated with Neurofibromatosis type 1 (NF1). Because NF1 is associated with a high likelihood of tumor formation, it is critical to distinguish it from other posterior mediastinal cancers such as neurofibroma, neuroblastoma, and ganglioneuroma. Scoliosis is the most frequently observed feature in NF1 patients with spinal deformities. Moreover, there are several distinctive radiographic features, including dural ectasia, defective pedicles, and spondylolisthesis, which are relatively less common in these patients. Surgery may be performed for stabilization of the spine. 

The present study reports on a 62-year-old female with neurofibromatosis type 1 who was referred for an unusual chest X-ray and chest Computed Tomography (CT) revealing a thoracic mass while she was hospitalized and under observation for dyspnea. The chest X-ray film showed homogenous opacity with a well-defined margin in the right apex. The chest CT showed an enlarged intervertebral foramen and defected vertebral arch around the mass and scoliosis. Although the pre-operative diagnosis was dumbbell type neurinoma, the tumor was found to be a protrusion of dura mater with spinal fluid out of the spinal canal. Part of the wall was excised, the residual opening was repaired, and surgical stabilization was performed. 

Retrospectively, magnetic resonance imaging showed the characteristics of thoracic dural ectasia and anterior meningocele, which, in an asymptomatic case, require regular radiographic follow-ups. Surgical intervention is an alternative for patients with spinal deformities or symptomatic patients due to the adverse effects of spinal cord compression and mediastinal structures.