A Dumbbell-Shaped Meningioma Mimicking a Schwannoma in the Thoracic Spine

ABSTRACT

A 50-year-old man presented bilateral hypesthesia on and below the T6 dermatome and paresthesia. Magnetic resonance imaging (MRI) showed an intraspinal extradural tumor, which located from the 6th thoracic vertebral body to the upper margin of the 7th vertebral body, continuing dumbbell-like through the intervertebral foramen into the right middle thorax suggesting a neurogenic tumor (neurofibroma or neurilemmoma). With the patient in a prone position, we exposed and excised the tumor via a one stage posterior approach through a hemi-laminictomy of T6. Histologic examination showed a grade 1 meningothelial meningioma, according to the World Health Organization classification. Initially, we assumed the mass was a schwannoma because of its location and dumbbell shape. However, the tumor was actually a meningioma. Postoperatively, hypesthesia resolved completely and motor power of the leg gradually full recovered. A postoperative MRI revealed no evidence of residual tumor.