Granular Cell Tumor of the Intradural Extramedullary Spinal Cord : Report of Two Cases with Respect to Radiological Differential Diagnosis
A 22-year-old woman was admitted to the outpatient department with a 1-month history of left leg weakness and hypesthesia below the T2 level. Magnetic resonance (MR) images showed a 2.2×1.3 cm tumor at T1-2 (). The margin of the tumor was well defined, and the neural foramen was widened by the tumor, suggestive of a slow-growing tumor. The tumor showed broad isointensity with respect to the spinal cord on T1- and T2-weighted MR images and demonstrated homogeneous enhancement of the tumor on T1-weighted images. The tumor demonstrated an unusual pattern of internal low signal speckled dots on T1 enhanced MR images ().\nThe patient underwent T1-2 laminoplastic laminotomy, and the tumor was exposed. The tumor looked similar to a typical schwannoma, appearing pearly yellow and white, with eccentric attachment to a nerve root. Although the tumor was friable, its capsule was tough and adhered tightly to the root. The two roots adhering to the capsule were sacrificed. At the completion of the resection, there was no change in the electrophysiological monitoring. On the histological exam, the tumor cell had abundant cytoplasm with eosinophilic granules (). Immunohistochemical analysis showed the tumor cells were strongly and diffusely immunoreactive with S-100 protein and CD68. The patient's hypesthesia improved after surgery. Follow-up MR imaging performed 12 months after surgery showed no evidence of recurrence.