The authors present two case-reports of spinal lipomas, which belong among closed neural tu be defects. The aim of the study is to point out the role of age at the time of surgical intervention. Some of the clinical signs were the same in both patients studied. In neonatal age the only symptom of congenital anomaly was skin malformation in the midline of the lumbosacral region without deterioration of neurological function. Changes of this function, resulting from the tethered spinal cord, appeared later and progressed. Only then was the exact diagnosis established and surgery performed. MRI, operative and histological findings confirmed a nearly identical type of malformation. From the split conical end of the spinal cord, which was in a lower position, a lipoma arose with no extension to the central canal. Through the dural defect and spina bifida it continued extradurally to the subcutaneous tissue. Nearly complete excision was possible in both patients. Skin manifestations of the malformation were different in the two patient. The first patient (female) had a tumour and skin haemangioma in the lumbosacral region. A dermal sinus pointed to th e existing anomaly in the second patient (male). The two patients differed as to the age of manifestation of neurological dysfunction and surgical intervention, as well as to their postoperative functional reversibility. The first patient was operated at the age of 10 months. Now, 19 months after surgery, she is asymptomatic, the functional changes proved to be completely reversible. The second patient experienced the first functional problems at the age of 12 years and they progressed during the following years. He was operated when 14 years old. One year after the operation a slight reversal of functional changes was recorded, but no further improvement occurred later on. The age seems to have played an important role in the reversal of deteriorated functions of patients with a tethered spinal cord caused by spinal lipoma.

        Key words: spinal lipoma, spina bifida, neural tube defect, tethered spinal cord