[Intraspinal lipoma in an infant: a case report of MRI study].

A 6-month-old boy having intraspinal lipoma with lumbosacral subcutaneous lipoma and occult spinal dysraphism is described. CT scan and magnetic resonance imaging (MRI) are demonstrated. On admission, the patient showed no neurological deficits. Lumbosacral hemangioma and subcutaneous lipoma were noticed on physical examination. A plain spinal roentogenogram revealed occult spinal dysraphism extending from L 4 level down to the sacral region. A plain CT scan disclosed a round-shaped low density area surrounded by a relatively high density area corresponding to the neural tissue in the spinal canal. MRI (1.5-T superconducting system) with sagittal views clearly showed an oval-shaped high signal intensity (SI) area-an intraspinal lipoma-with the neural tissue running longitudinally within and on its surface. The lipoma appeared to be attached to the spinal cord at L 1/2 level. On operation, we found an extramedullary lipoma which had a certain connection to the sacral epidural adipose tissue with an opening of the dural sac, as far as the subcutaneous lipoma. Tethered cord and thickened filum terminale were not identified. Generally, lipoma is demonstrated as a low density area of approximately -90 H.U. on a CT scan. In MRI, we can obtain a high contrast between the lipoma, the spinal cord, and the cerebrospinal fluid, since they are shown as a high, an intermediate, and a low SI area respectively, on T1-weighted spin echo images. Furthermore, sagittal section of MRI is regarded as a potent diagnostic modality to get the precise anatomy of the spinal cord lesion. These short spin echo images can be taken in a relatively brief time. It is a great advantage for patients with spinal lipoma, who are usually infants. MRI is considered to be a quite useful modality to diagnose spinal lipoma, and is able to lead to an early diagnosis non-invasively and accurately, facilitating appropriate surgical treatment.(ABSTRACT TRUNCATED AT 250 WORDS)