A 16-year-old high school male student was admitted to King Abdulaziz University Hospital with complaints of progressive weakness and ascending numbness of the lower limbs. This student is a healthy professional basketball player, who had been experiencing difficulty jumping over the course of one year. The weakness progressed gradually in an ascending fashion to involve the lower limbs. His presenting paraparesis was followed, a few months later, by a progressive ascending numbness in the lower limbs as well. His symptoms had worsened rapidly over the period of three months preceding his admission to our hospital, to the extent that he had difficulty in urination and became confined to a wheelchair. His past medical history was negative, with no history of drug intake, particularly corticosteroids. Over the course of the year prior his admission, he was evaluated in several clinics using electrophysiological and magnetic resonance imaging (MRI) studies and cerebrospinal fluid analysis, which were reported within normal. Several working diagnoses were proposed, including ascending motor paralysis, transverse myelitis, and tropical myelitis.
Physical examination on admission revealed a well-nourished male patient who weighed 60 kg and measured 160 cm tall (body mass index of 24). There was no spinal deformity; one cafe au lait spot measured 10 mm in the lower thoracic region was noted. There was marked plantar flexion deformity of his feet with an associated hyperextended inverted toe. Neurological examination of his cognitive function and cranial nerves were within normal ranges. Motor examination of the lower limbs revealed a significant hypertonia and weakness, which were mostly distal with grade 2-3 and 4 proximal. He had bilaterally hyperactive deep tendon reflexes in the lower limbs with Babinski signs and sustained ankle clonus. Sensory examination revealed hypoesthesia and impaired proprioception in lower limbs, with decreased sensation up to the level of the 5th thoracic dermatome. The motor and sensory examination of the upper limbs was normal.
On investigation, routine laboratory blood tests including complete blood count, liver function, and renal function analysis were within normal ranges. A repeat MRI study of the thoracic spine revealed marked compression of the spinal cord from a large dorsally located extradural mass extending from the T-4 to T-12 vertebral bodies (Fig. 1). This mass had a maximum thickness of 10 mm in the middle, tapering at both the T-4 and T-12 vertebral bodies, and the spinal cord appeared to be displaced and compressed anteriorly against the posterior aspect of the vertebrae, with a significant reduction in the AP diameter of the spinal cord. Despite the marked compression, there was no spinal cord signal abnormality. The epidural lipomatous mass followed the normal fat signal in both pre-and post-suppression techniques. The post contrast images did not reveal any significant enhancement. There was no evidence of disk or vertebral column signal changes, and brain MRI study was normal.
The patient underwent posterior thoracic laminoplasty from T4 to T10 vertebral levels. A dorsally located and relatively vascular firm epidural fatty tissue was encountered, which was not infiltrating the bone or the dura; it was dissected easily and completely removed in one piece. Histological examination of the operative specimen demonstrated vascularized mature fibro-fatty tissue consistent with the diagnosis of lipomatosis (Fig. 2). The patient had an uneventful postoperative period; within a week, he was experiencing gradual improvement in his paraparesis, his numbness had diminished, and he was able to walk with support. He was discharged on the 9th postoperativeday.
He continued to show progressive neurological improvement with extensive outpatient physiotherapy program and was able to walk unassisted after 3 months. His sphincter function had recovered with adequate spinal cord decompression on follow-up MRI scan (Fig. 3). At 4-year follow-up, his examination revealed a completely recovered neurological function.