Multiple subpial lipomas with dumb-bell extradural extension through the intervertebral foramen without spinal dysraphism.
BACKGROUND: Intradural subpial lipomas not associated with spinal dysraphism, account for less than 1% of spinal cord tumors. The simultaneous existence of multiple intradural subpial lipomas with dumb-bell extradural extension through the intervertebral foramen in the same patient without any evidence of spinal dysraphism has not been previously reported. CASE DESCRIPTION: A 38-year-old man presented with progressive spastic paraparesis, and weakness of right elbow extension and opposition of the medial three fingers. He also had ascending paraesthesia from the C6 dermatome to the saddle region and loss of joint and position sense of both lower limbs with hesitancy and precipitancy of micturition. There was no spinal tenderness, deformity, neurocutaneous markers, or spinal dysraphism. The total duration of illness was 11 years. The oblique views of the plain radiographs of the cervical spine revealed an enlarged right C7-D1 intervertebral foramen. The T1- and T2-weighted magnetic resonance (MR) images showed two intradural, hyperintense lesions (with extensive loss of signal on fat suppression sequences), one extending from C5 to D2 and the other opposite the C3-4 disc space. The parasagittal and axial images showed the extradural component of the lesion emerging from the right C7-D1 intervertebral foramen. At surgery, a C2 to D2 laminectomy was performed. The lipoma, enclosed in a fine pial membrane, was situated on the right posterolateral aspect of the cord. The right-sided nerve roots from the C6 to D1 levels were completely enmeshed by the lipoma. There was a separate superficial subpial lipoma adherent to the posterior aspect of the cord at the C3-4 level. A distinct area of normal cord was present between the two lesions. A subtotal decompression of the lesions including the component emerging through the right C7-D1 intervertebral foramen and a duraplasty were performed. At follow-up after 18 months, the posterior column impairment, lower limb hypoaesthesia, and right upper limb paraesthesia had improved. However, residual elbow extension and lower limb weakness, mild lower limb spasticity and sphincteric dysfunction persisted. CONCLUSIONS: The multiplicity of intradural subpial lipomas without spinal dysraphism points to a dysembryogenetic basis similar to that seen in patients with spinal dysraphism that results in lipomas, but in which the defect is not severe enough to give rise to coexisting vertebral and soft tissue anomalies. The dumb-bell extradural extension through the intervertebral foramen is extremely rare. The magnetic resonance imaging and surgical principles are discussed.