Spinal cord lipoma

May occur in conjunction with spinal dysraphism, see Lipomyeloschisis. The following considers lipomas that occur in the absence of spinal dysraphism.

see Nondysraphic intramedullary lipoma

Intramedullary lipomas are rare spinal cord tumors and account for about 1% of all spinal neoplasms.

Spinal cord lipomas tend to present in the pediatric population.

These lesions can occur anywhere along the length of spinal cord, but are frequently localized to the lower thoracic and lumbosacral levels.

see Lumbosacral lipoma.

Peak occurrence: 2nd, 3rd, and 5th decade. Technically hamartomas. No sex predominance. Usually ID-EM (a sub-type is truly IM and essentially replaces the cord31), cervicothoracic region is the most common location.

NB: unlike other IMSCT’s, most common symptom is ascending mono- or paraparesis (c.f. pain). Sphincter disturbance is common with low lesions. Local subcutaneous masses or dimples are frequent.

Shimizu et al. describe differentiation of a spinal intramedullary lipoma from an intramedullary hematoma on magnetic resonance images (MRI) with fast spin-echo (FSE) sequences. A 60-year-old man with dysesthesia in the legs and gait disturbance, was suspected of having myelopathy at a middle thoracic lesion. MRI with FSE sequences revealed an intramedullary lesion at T7 to T8. On the basis of hyperintensity on both T1-and T2-weighted images and a perilesional hypointense rim on T2-weighted images we made a diagnosis of subacute hematoma and planned observation. However, computed tomography for associated vertebral degeneration revealed a hypodense area (-97 Hounsfield units) in the region corresponding to the lesion depicted by MRI. They revised the diagnosis to an intramedullary lipoma and debulked the lesion. The lipoma was surrounded by a thick whitish capsule. Histopathologically, the capsule contained mature fat tissue and abundant collagen. The initial diagnosis was mainly attributable to specific FSE characteristics, i. e., the depiction of fat tissue as hyperintense on both T1-and T2-weighted images. Conventional spin-echo MRI depicts fat tissue as hyperintense on T1-and as hypointense on T2-weighted images. Other factors contributing to our initial diagnosis were MRI findings suggestive of an intramedullary hematoma, i. e., the intrinsic location of the lesion and the perilesional hypointense rim on T2-weighted images ascribable to collagen present in the capsule. The accurate diagnosis of an intramedullary lipoma on FSE requires correct interpretation of the signal, which is different from the signal on conventional spin-echo MRI ¹⁾.

Malis recommends early subtotal removal at about 1 year of age in asymptomatic patient.

Superficial extrasacral removal is inadequate, as patients then develop dense scarring intraspinally leading to fairly rapid severe neurological damage with poor salvage- ability even after the definitive procedure.

The 20-year outcome of 315 patients who had total resection is measured by overall progression-free survival (PFS, Kaplan-Meier), and by subgroup Cox multivariate hazard analysis for the influence of four variables: lipoma type, symptoms, prior surgery, and post-operative cord-sac ratio. These results are compared to 116 patients who underwent partial resection, and to two published series of asymptomatic lipomas followed without surgery. The PFS after total resection for all lipomas is 88.1% over 20 years vs. 34.6% for partial resection at 10.5 years (p < 0.0001). The PFS for total resection of asymptomatic virgin lipomas rose to 98.8% vs. 60% and 67% for non-surgical treatment. Partial resection also compares poorly to non-surgical treatment for asymptomatic lipomas. Multivariate analyses show that a low cord-sac ratio is the only independent variable that predicts good outcome. Pre-operative profiling shows the ideal patient for total resection is a young child with a virgin asymptomatic lipoma, who, with a PFS of 99.2%, is essentially cured. The technique of total resection can be learned by any neurosurgeon. Its long-term protection against symptomatic recurrence is better than partial resection and conservative management. The surgery should be done at diagnosis, except for asymptomatic small infants in whom surgery should be postponed till 6 months to minimize morbidity ²⁾

A 31 year-old woman presented with bilateral numbness in her hands and a burning and aching sensation in her arms for ∼ 6 months. The patient did not have any weakness or myelopathic signs. Magnetic resonance imaging T1 showed a T1 hyperintense, T2 hypointense, non-contrast-enhancing mass on the dorsal aspect of the spinal cord with significant compression. The patient underwent a dorsal cervical laminectomy with subtotal resection of an isolated cervical lipoma with an exophytic component. The pathology confirmed the diagnosis of a lipoma.

Surgical management of this rare pathology has a wide variety of options. Depending on the neurologic deficits, observation to gross total resection may be reasonable options. In this case, a subtotal resection was achieved with no further worsening of neurologic symptoms ³⁾.