[Lipoma of the filum terminale: a prospective tomodensitometry study]

A lipomatous aspect of the filum terminale is sometimes recognized in routine lumbosacral CT studies as a small (1 to 2 mm) tubular fatty hypodensity that lies posteriorly in the dural sac. To study the epidemiologic frequency and pathological significance, the authors prospectively reviewed the standard lumbosacral CT studies of a large series of 1033 adult patients suffering from mechanical problems. The lipomatous aspect was encountered in 39 of them (3.77%). The average size was about 1 mm and never exceeded 2 mm (92%) except for 3 cases. The commonest site was L4-L5 but the anomaly was more commonly seen at two levels. Despite the lack of histological proof, the authors consider the lesion benign and trite with two restrictions: the pediatric cases (not studied in their series) and the patients presenting a lipoma greater than 3 mm; for these two groups further investigations are recommended to exclude a tethered cord syndrome.