Pan Arab - Intramedullary

INTRODUCTION

Spinal cord lipomas without associated spinal dysraphism are uncommon, accounting for 1% of spinal cord tumours.5,7,8 These mostly involve the cervicothoracic region and their growth causes ventral flattening of the cord and separation of the posterior columns.4,7 Magnetic resonance imaging (MRI) provides information regarding the location so that adequate decompressive surgery can be performed.4,9,12 We report our experience with four cases of intramedullary lipoma that were treated surgically in our institution and discuss the possible pathogenesis, clinical, radiological and therapeutic aspects of these lesions.

CASE REPORT

Patient 1: A 15-year-old female, with unremarkable past medical history presented with painful dysesthesia in the interscapular and thoraco-lumbar areas, followed by gait disturbances. Symptoms started 3 months prior to presentation. Clinical examination revealed spastic paraparesis with difficult gait, hypoesthesia with T6 sensory level and sphincter disturbances. Plain x-ray showed spinal cord enlargement from C7 to T5, associated with thoracic scoliosis. Myelography by suboccipital approach demonstrated a complete block of the spinal canal. Computed tomography (CT) scan showed a large low density mass (-30 to –130 HU) displacing the cord and extending from C6 to T6. Nature of this mass was suggestive of a lipoma. Laminectomy from T6 to C6 was performed. There was a large intradural intramedullary mass without clear cleavage plane between the spinal cord and the tumour. Partial resection with duraplasty was performed. Pathological examination confirmed the diagnosis of lipoma. There were no postoperative complications. Follow-up during 14 years has shown no evidence of progression.

Patient 2: A 15-year-old patient was admitted to our institution in January 1988 with low back pain of several months’ duration. The pain was in the lower interscapular area and radiated to the right side of the chest. The patient denied any weakness in the legs or bladder and bowel difficulties. General and neurological examinations were within normal limits. Plain x-ray film of the spine showed spinal canal enlargement and pedicular erosion from T1 to T7. Myelography revealed a complete block at T7. CT scan showed intramedullary fatty lesion extending from T2 to T7 (Fig. 1). Surgical exploration consisted of laminiectomy. At dural opening, the intramedullary location of the tumour was confirmed. Biopsy and duraplasty was made. Histological examination revealed that the tumour was composed of mature fatty tissue. The post-operative course was uneventful with slight clinical improvement. Six years later neurological examination was normal.

Patient 3: This otherwise healthy 43-year-old man was admitted to our institution with 2-month history of neck pain and bilateral brachalgia associated with progressive weakness of the lower and upper limbs and difficulty in walking. There were no bladder or bowel disturbances. Examination revealed a flaccid type of distal weakness with hyporeflexia of both upper limbs. There was a spastic paraparesis with brisk tendon jerks, up going plantars and sustained ankle clonus bilaterally. Pain and temperature sensations were reduced from T4. Vibration and joint position senses were normal. X-rays of the cervicothoracic spine showed evidence of pedicular erosions. Lumbar myelography demonstrated complete block at T4. CT scan showed an intramedullary fatty lesion (-95 HU). At operation decompressive laminectomy C3 to T4 was performed. There was a lipomatous intramedullary tumour without clear cleavage plane between the tumour, spinal cord and the roots. Surgery was limited to a biopsy. Histological examination confirmed it to be a mature lipoma. Post-operative course was uneventful and follow-up at 3 years revealed no abnormality.

Patient 4: A 16-year-old female was admitted to our institution in February 1998 with a history of slowly progressive weakness of lower and upper limbs and sphincter dysfunction that developed over a 6-month period. Physical examination revealed spastic tetraplegia with 0-1/5 strength in all muscle groups of the upper and lower limbs. There was hyporeflexia with sensory level at C6 and impaired position sense. MRI showed a solid intramedullary tumour from C6 to T1 vertebrae with expanded spinal cord. Its signal intensities on both T1– and T2– weighted images was suggestive of a fatty mass (Fig. 2). At operation, C5 to T5 cervicothoracic laminectomy was done showing dural tube to be tense and non-pulsatile without epidural fat. Intradural inspection demon-strated a lipomatous lesion arising dorsal to the spinal cord (Fig. 3). The lesion was partially resected using microsurgical technique and ultrasonic aspirator. Sufficient resection was possible to allow dural closure without tension. Histopathological examination showed mature fatty cells (Fig. 4). Post-operative course was uneventful with progressive resolution of neurologic symptoms. Post-operative rehabilitation showed good results. Twenty days after surgery, the patient started walking with support. Control MRI showed that over 50% of the lesion was removed (Fig. 5). Eight months later, she had normal strength in all muscle groups of upper and lower extremities and she returned to school.

	Figure 1		Figure 2
	Figure 1 - CT scan shows a large low density mass (-80 HU) occupying almost all of the spinal canal area shifting the cord.		Figure 2 - Sagittal T1-weighted image of a solid cervicothoracic intramedullary lipoma with signal characteristics of fat.

	Figure 3
	Figure 3 - Pre-operative view showing the intramedullary lipoma.

	Figure 4		Figure 5
	Figure 4 - Photomicrograph of excised tissue showing some strands of peripheral nervous tissue amidst mature fat cells (H & E x 100).		Figure 5 - Control MRI showing residual lipoma and spinal cord decompression.