脊髄軟膜下脂肪腫の5症例における病態と治療指針の検討  [in Japanese] Subpial Spinal Lipoma : Report of Five Cases and Discussion about the Pathogenesis and Treatment Modality  [in Japanese]

Subpial spinal lipoma (SPL) is a rare tumor with an incidence of 1% of primary spinal cord tumors. The few scattered reports of SPL have described its generally poor prognosis and lack of improvement following surgery. We report 5 cases of SPL and discuss the difficulties associated with its treatment (7 surgeries). Among 66 cases of spinal cord tumors encountered at Jikei University School of Medicine, Japan, between 1998 and 2003, 5 cases were diagnosed as SPL and 7 surgeries were performed (including 2 reoperation cases due to deterioration). Postoperative outcome was unchanged following 3 surgeries, including 1 reoperation case and deteriorated following 3 cases, 4 surgeries. Deterioration in the 3 cases (including both reoperation cases) was caused by extensive removal of the SPL (n=1), postoperative kyphotic deformity (n=1) and was probably caused by adhesive arachnoiditis due to the re-operation (n=1). These treatment results were unsatisfactory. SPL has a different pathogenesis from the lipomas associated with dysraphism. However, compressive factors appear to play an important role in the etiology of spinal damage, as malformative or hamartomatous lipoma cause neurological deficit at some ages. Therefore, biopsy or insufficient removal of the SPL might not prevent the progression of symptoms. On the other hand, extensive removal sometimes results in spinal injury. In addition, deformity of the vertebra should be considered. Decompression of the spinal cord due to partial removal of SPL, and reconstructive laminoplasty for alignment might be the best surgical option.