Intrarachidian lipomas. Observations on 4 cases and pathogenetic considerations.

The Authors report 4 cases of spinal lipomas: 2 intradural, 2 completely intrarachidian extradural. The intradural lipomas observed were 2 cases in the lumbo-sacral area, both operated on by the partial removal of the lesion with very good clinical results; histologically they were found to be 2 fibrolipomas. The 2 cases of extradural lipomas, completely intrarachidian, were situated in the thoracic and lumbar areas. Both were operated on with very good results and it was possible to remove all the lesion. They were found to be an angiolipoma and a mature lipoma. On the basis of the literature, the Authors maintain that, for these cases of intradural lipoma, the disembryogenetic hypothesis (such as embryological ectopia) should be accepted as etiopathogenesis. They point out the nature and origin of extradural lipomas, arising in a site where adipose tissue is abundant, have never aroused interest on their origin, but they too can be considered malformative lesions of the hamartomatous type and not neoplastic lesions. These data are confirmed by the remarkable frequency in these cases of the mixed variety of lipoangiomato or angiomiolipomatosis. The Authors thus underline the importance of the relationship between the presence of a subcutaneous lipoma in cases of completely intrarachidian extradural lipomas to support the hypothesis of malformative origin.