Non Dysraphic Intramedullary Spinal Cord Lipoma
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.360941
Source of Support: None, Conflict of Interest: None
Keywords: Intramedullary lipoma, non-dysraphic
Intramedullary spinal cord lipomas are very rare lesions which accounts for less than 1% of all intramedullary spinal cord tumors. These tumors are in most cases associated with spinal dysraphism in which it will likely be seen communicating with the subcutaneous tissue via the defect in the posterior elements of the spine. First case report of spinal lipoma was done by Gowers in 1876., There are only a few cases that have been reported worldwide.
A 17-year-old female presented with upper dorsal pain for duration of 1 year with tightness followed by weakness of both lower limbs [left > right] for 30 days duration. Bedridden for 1 day with no bowel and bladder symptoms. On examination she was found to have grade IV spasticity, lower limb power- proximal 4/5 - distal 3/5. The patient had loss of touch, pain, pressure, temperature, position and vibration sensation below D4 dermatome. Deep tendon reflexes in lower limb was exaggerated. No neurocutaneous markers.
Imaging studies done showed T1 and T2 WI hyperintense lesion of size 12.5 × 1.2 cm in dorsal intramedullary region causing cord compression [Right > Left] with distal syrinx formation. This lesion appeared hypointense in fat suppression sequence.
Patient was taken up for surgery, operated in prone position. Midline skin incision made extending from D1 to D10 spinous process. Laminotomy was done and dura was found to be tense and bulging. Midline durotomy done. Arachnoid membrane separated in midline. Yellowish tumour encountered and subtotal excision done with Cavitron ultrasonic surgical aspirator with minimal handling of the cord. Excision was done from above to below till normal cord is seen and leaving a sliver of tumour which is adherent to the underlying cord. Laminoplasty was done as it was involving long segment and to avoid delayed kyphosis [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]. Postoperative period was uneventful. Spasticity improved to grade II over 2 weeks. Patient improved neurologically with physiotherapy. Diagnosis of lipoma confirmed with histopathology.
Non-dysraphic spinal cord lipoma is the least common intramedullary tumor, with similar presentation to other intramedullary spinal cord tumors. Lipoma is located below the pia mater. These are not true neoplasm, but arise from inclusion of normal mesenchymal tissue. Only 7 cases of true intramedullary spinal cord lipoma was reported before 1957. Lee et al. reported that only 100 cases of spinal cord lipomas were reported worldwide before 1995. H.S. Bhatoe et al. in 2005 did a retrospective analysis of 14 patients from 1991-2003. Symptoms vary depending on the site of the tumor. Usually, patients present with longstanding disability followed by rapid progression of their symptoms. By the time they arrive to the hospital they will have poor neurological condition. Due to the absence of clear surgical plane between tumor and spinal cord most surgeons find it difficult to remove this tumor. The goal of surgery is to provide decompression and generous debulking, leaving a sliver of tissue to prevent vascular compromise of adjacent cord, followed by duraplasty.
Patterns of presentation
In infancy or childhood
It usually presents as tetraplegia or floppy baby syndrome, which was initially thought to be due to birth related trauma.,
In 3rd or 4th decade of life
This type of disease presents as slowly progressing myelopathy which can remain static for years with spinal axis pain and dysesthetic sensory changes. Plane of lesion will be mostly subpial. These patients will remain ambulant and continent for a long time with sudden deterioration one day, which indicates exhaustion of physiological reserve of neurological functions of spinal cord which was compressed for years by the congenital lesion.
Hypothesis for intramedullary lipoma
Developmental error theory
Mesenchymal cells, precursor to adipocytes migrates into neural tube before closure and develops as lipoma.
Connective tissue metaplasia is the cause of formation of lipoma.
Hamartomatous origin theory
Adipocyte tissue can comprise peripheral nerve twig, dermoid cyst, skeletal muscles and lymphoid or renal tissue, which arises from ectoderm or mesoderm.,
Spinal vessel cell theory
Defective neural crest cells fail to inhibit mesenchymal cells which forms adipocytes instead of forming into spinal vessels in normal situations.
In some lipomas, other mesenchymal derivatives are also seen. Lipomas with spinal dysraphism are thought of as hamartomas, whereas non-dysraphic lipomas are presumed to be true neoplasms.
Lee et al. says that spinal lipoma is a congenital lesion and not a neoplasm. They have actually replaced normal tissue during development in addition to compression, therefore there would be more chance of everlasting injury to function of normal spinal cord due to less redundancy in the functional pathways. Intramedullary spinal cord lipoma without spinal dysraphism has less space for enlargement; hence they have early presentation of symptoms. Asymptomatic lesions can be on observation but once there is commencement of deficits, surgical debulking is advised.
Lee et al. says that early surgery is always better because it prevents permanent spinal cord injury. Operating after the patient developed irreversible spinal cord dysfunction is futile. Early diagnosis with MRI followed by surgical debulking of lesion prior to irreversible disease progression is ideal.
MRI is the most sensitive and definitive investigation of choice. Lesion will be hyperintense in T1 weighted image and confirmed by fat suppression sequence, in which blood and calcifications remains hyperintense.
The aim of the surgery should only be biopsy and decompression by partial debulking, which is achieved by leaving a thin strip of lesion on the surface of the cord. Attempts in trying to remove the adherent tumor attached to the cord leads to worsening of neurological deficits. It is better to leave a thin layer of tumor over the cord since the tumor has indolent growth.,, Intraoperative ultrasound is helpful to know the extent of lesion. SSEP monitoring will be helpful.
CO2 laser is helpful as laser vaporizes the fatty tissue which has high water content. Intraoperative neuromonitoring improves postoperative outcome. Laminoplasty is a reasonable option in adults as it helps in avoiding delayed instability.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]