Comparative Evaluation of MR Imaging Findings of Spinal Neurilemmomas and Neurofibromas

PURPOSE:To find out the differential points between spinal neurilemmomas and neurofibromas. MATERIALS AND METHODS: Fourteen patients with pathologically proven neurilemmomas(n--6) and neurofibromas(n=8) of spinal canal were studied using magnetic resonance(MR) imaging. Contrast enhancement was performed with Gd-DTPA in all 14 patients. The size and shape of the tumor, absence or presence of adjacent bone erosion, location and extent of the tumor, signal intensity, degree and pattern of Gd-DTPA enhancement of the tumor were retrospectively analyzed. RESULTS: Rim enhancement was seen in five of six patients(83%) with neurilemmomas and three of eight patients(38%) with neurofibromas. Neurilemmomas showed moderate to marked enhancement in five of six patients(83%), whereas neurofibromas showed moderate to mild enhancement in all 8 cases(100%). The average size in longest diameter of the tumors was 2.8cm in neurilemmomas, while 5.4cm in neurofibromas. Neurilemmomas showed ovoid shape in 5 of 6 patients, no extra- or intradural extension, and erosion of adjacent bone in one patient, whereas neurofibromas showed Iobular shape in 6 of 8 patients, extra- or intradural extension in 6 of 8 patients, and erosion of adjacent bone in 4 of 8 patients. CONCLUSION: In differentiating neurofibroma from neurilemmoma, size, shape, extent of the tumor, absence or presence of adjacent bone erosion, and pattern and degree of enhancement of the tumor may be helpful.