Imaging Appearances and Pathologic Characteristics of Spinal Epidural Meningioma

Spinal epidural meningioma is an uncommon tumor. This study aimed to analyze the imaging and pathologic characteristics of this rare tumor. Fourteen confirmed cases of epidural meningioma were retrospectively reviewed, and imaging characteristics and pathologic findings were analyzed to identify the typical features. The mean age of the patients (4 men, 10 women) was 44.9 years. Twelve tumors were in the cervical spinal canal, and 2, in the thoracic spinal canal. There were 9 en plaque meningiomas, 4 dumbbell-shaped meningiomas, and 1 fusiform/ovoid meningioma. The epidural meningiomas extended over 2-5 spinal segments (mean, 3.2 spinal segments). A soft epidural mass was seen in 12/14 (86%) patients. Dural calcification was seen in 8/14 (57%) tumors. Tumor caused intervertebral foramen enlargement in 10/14 (71%) patients and adhered to the nerve roots in 11/14 (79%) patients. Intradural invasion was seen in 8/14 (57%) patients. The dural tail sign was present in 13/14 (93%) tumors on contrast-enhanced T1WI. Regarding pathologic type, 10 of 14 (71%) were psammomatous, 2 of 14 (14%) were meningothelial, 1 of 14 (7%) was angiomatous, and 1 of 14 (7%) was transitional. During follow-up (mean follow-up, 73.4 months; range, 4-192 months), 7 patients had recurrence. Recurrences were between 4 and 192 months after the operation. Epidural meningioma has 3 different growth patterns. Dural thickening, calcification, invasion, and epidural mass formation are characteristic features of epidural meningioma. Regular follow-up imaging is required to detect recurrence.