文摘
Objectives: The incidence of intramedullary lipoma or epidermoid is less than 1 % of all spinal tumors, particularly in adulthood. A variety of concurrent spinal anomalies can be found: from occult spinal dysraphism, dermal sinus tracts, hypertrichosis, spina bifida, to dural bands, tethered spinal cord with thick filum terminale to lipoma, epidermoid, diastematomyelia and lipomeningomyelocele. The typical manifestation in the elderly is low extremity pain, weakness, paresthesia, paraparesis, hyperreflexia and sphincter disorders. The onset of symptoms occurs often after sudden stretching or after low-intensity trauma, but relatively asymptomatic development can be found over a longtime period. Method: The authors present their experiences with three patients over a 20-year period. Intradural exploration was performed in two cases; microsurgical technique was used and all associated anomalies were operated on during the same operation. Results: MR was the imaging tool of choice. Diagnosis of lipoma is based on the T1 and T2 image with high-signal intensity, contrary to epidermoid (T1 low intensity, T2 very high-signal intensity and proton density differing from CSF, image possibly inhomogenous, sharply marginated or lobulated). Enhancement effect is not present in both lesions. The findings of the MRI were difficult to interpret. Microsurgical treatment differs in this. For epidermoid, we recommend intracapsular decompression and radical removal of the capsule, the only growing part of the tumor, with close adherence to the neurovascular structures, because the remnant can produce recurrency of the lesion. In spite of this fact, lipoma is the nongrowing part of this common lesion, and there is no cleavage space between the medulla and tumor. Therefore, only partial removal with a safe strip of tissue left is recommended. The treatment of concurrent anomalies is mandatory. Conclusion: The conventional explanation for clinical symptoms is tethering of the anchored spinal cord, stretching and low-intensity injury or, more often, involution changes. The authors also suggest that progressively slow linear growth with compression of the neurovascular structures can cause late clinical manifestations in the elderly. On the basis of their limited experiences, the authors do not recommend prophylactic surgery in asymptomatic or stabilized patients.