Nondysraphic intradural spinal lipoma.

Sir,

A 12 year-old girl presented with progressive weakness of both lower limbs, difficulty in walking, and numbness in her legs since the last two months. She had become bedridden for the last one week. Clinical examination did not reveal any stigmata such as dimples, hair, fistulae, or any mass on her spine. Neurological examination showed spastic paraplegia with 0/5 grade bilateral power. All sensations were markedly diminished below the D5 level. MRI scans revealed a hyperintense, elongated mass lesion on the saggital T1W and T2W images between the D3–D8 segments [Figure 1]. Axial T1W image showed that the lipoma was situated dorsal to the spinal cord [Figure 2]. A D3-D8 laminectomy was done and the duramater was opened in the midline and retracted. A lipoma was identified on the posterior aspect of the cord and there was no clear surgical cleavage between the cord and the tumor. Subtotal excision was carried out. No significant improvement was seen in the neurological status at the six months’ follow-up and the patient was referred for physiotherapy and rehabilitation. However, the patient was lost to follow-up subsequently.

Figure 1

Sagittal T1- and T2-weighted images showing hyperintense lesion extending from D3–D8 level (arrow)

Figure 2

Axial T1W image showing the hyperintense lipoma situated posterior to the spinal cord

Intradural spinal lipoma (ISL) constitutes approximately 1% of all spinal tumors and is usually associated with lumbo-sacral spinal dysraphism.[1] ISLs unassociated with spinal dysraphism are rare with only a few cases being reported in literature.[2-6] They are seen in children and young adults and are situated on the posterior aspect of the spinal cord in the cervico-thoracic or thoracic regions. They show equal gender incidence but are reported to show aggravation of symptoms during or after pregnancy.[3] The patients usually present with a long history of disability followed by a rapid progress of symptoms. The presenting complaints are spastic weakness in the extremities, dysestheic sensory changes, and gait difficulties. The neurological deficits are initially subtle and the history can span many years before the patient seeks medical attention. Theories about their pathogenesis are controversial, but the malformation theory wherein inclusion of the misplaced adipocytes during the formation of the neural tube causes the growth of lipoma . Thus, this is a hamartoma rather than a true neoplasm, which also explains the dorsal location of the lipoma.[3] Some believe intraspinal lipomas are congenital lesions and would not only compress, but also replace normal tissue during development.[6] A spinal lipoma without dysraphism has only a small space for expansion and thus, has an early presentation of symptoms as seen in our case.

ISLs adhere so closely to the adjacent spinal cord that they cannot be excised completely. Most symptomatic patients do not show any significant improvement in the neurological function after surgery. Hence, the operative principle should be decompression before symptom progression and subtotal resection wherever necessary.