Review and comparison of case reports
In this case, a cholesteatoma is in the lumbosacral region, and a long-segment lipoma is in the cervicothoracic region. The clinical manifestations and imaging features of lipoma is similar to syringomyelia, which can be confused. This is the first reported case of an intramedullary lipoma presenting similarly to syringomyelia. This case is the first report of intramedullary lipoma mimicking syringomyelia.
Syringomyelia is the result of an abnormal accumulation of cerebrospinal fluid in the central canal or spinal cord5. It is often secondary to Chiari malformation, tumors, and other diseases6. They can be distinguished by spinal MRI. Lipoma was hyperintense on both T1-weighted images and T2-weighted images, while the MRI scan of syringomyelia is similar to the cerebrospinal fluid, which shows hypointense on T1-weighted images and hyperintense on T2-weighted images, but they look similar on fat suppression sequence. In this case, MRI revealed a long intramedullary mass lesion at the level of C5-T7, which was relatively rare. And syringomyelia also has the characteristics of uniform long-segments on imaging, which can be confused.
There are syringomyelia cases mimicking intramedullary lipoma7,8 and an intramedullary lipoma case combined with syringomyelia9 (Table 1). In patients with intramedullary tumors, syringomyelia can occur either above or below the tumor. In recent years, two syringomyelia cases reported that the fluid component of syringomyelia sometimes contains fat droplets, which can appear as a non-solid lesion containing cholesterol similar to intramedullary lipoma on imaging. To distinguish it from conventional syringomyelia, it can be called "fatty syringomyelia". The cause and management of fatty syringomyelia and syringomyelia are the same. The occurrence of fatty syringomyelia and syringomyelia is not related to the underlying intramedullary lesions, that is, the type of tumor. In the cases of syringomyelia secondary to lipoma, patients have severe tethered cord syndrome9. Due to diffuse hypoesthesia, dyskinesia, and urinary incontinence in the lower extremities, the patient immediately went through decompression and tumor resection. The dislocation of the spinal cord and syringomyelia were relieved after the operation. Therefore, non-spinal dysraphism intramedullary lipoma and syringomyelia can both be secondary to other spinal tumors and can occur simultaneously. Some scholars have pointed out that the excess fluid, fat tissue, and even bone tissue in the spinal cord may be related to the instability of the spinal cord, which is the self-protection of the spinal cord7, but its mechanism needs further study.
Table 1
Synopsis of the most recent cases of syringomyelia similar to intramedullary lipoma and intramedullary lipoma combined with syringomyelia
Author, year
|
No. cases
|
Age, sex
|
Clinical manifestations
|
Location of lesion
|
Imaging features
|
Treatment
|
Late outcome
|
Mahdi et al.,20228
|
1
|
27, F
|
progressive neck pain and dysesthesia and tingling in the shoulders and upper limbs for 1.5 years.
|
Syringomyelia at C1-C5;
Pilocytic astrocytoma at C5-T2
|
MRI showed low signal on T1w, high signal occupying lesions on T2w at C1-5; T1w and T2w showed high signal occupying lesions at C5-T2
|
Tumor resection under the microscope
|
Neurological dysfunction was significantly improved and syringomyelia was resolved
|
Goel et al.,20207
|
1
|
32, M
|
burning pain over the entire right hand and right side of the chest and back for 2 years
|
Atlantoaxial dislocation
Syringomyelia at C5-C7
|
MRI T1w and T2w showed high signal occupying lesions at C5-7
|
Atlantoaxial lateral mass distraction fixation
|
Neurological dysfunction was not completely improved but syringomyelia was resolved
|
Luca et al.,20199
|
1
|
4, M
|
urinary incontinence associated with paraparesis, which quickly progressed and prevented ambulation.
|
Syringomyelia at T2-T7 and L5-S4
Lipoma at S3-S4
|
MRI showed low signal on T1w and high signal on T2w at T2-T7, L5-S4T1
MRI showed high signal occupying lesions at S3-S4
|
Spinal cord decompression and surgical tumor resection
|
Neurological dysfunction was significantly improved and syringomyelia was resolved
|
Controversies On The Treatment
Intramedullary lipoma and syringomyelia need different treatment. For syringomyelia and fatty syringomyelia, the underlying lesions should be relieved in general, and the syringomyelia will decrease and finally disappearance within one year. If it cannot be relieved or have acute symptoms, shunt decompression can also be performed. Whether surgical treatment should be performed for patients with intramedullary lipoma is still controversial. Pang10et al. believed that surgery should be performed as early as possible to prevent deterioration of neurological dysfunction and irreversible damage. However, Roujeau T11et al. believed that the improvement of neurological function after surgery was not ideal, and there was a high risk of complications. Lipoma is a benign tumor with a relatively stable course of the disease, which metabolic characteristic is the same as normal adipocytes and has a low probability of disease deterioration. Therefore, preventive surgery is not supported. If the symptoms occurred, surgical resection and decompression should be performed to relieve the spinal cord compression of the patient. Not total resection but subtotal resection is recommended if the lipoma deteriorates and invades the spinal cord. There is no significant difference in recurrence rate between the two groups, but the probability of neurological dysfunction after total resection is higher12. However, surgery rarely results in a complete cure in symptomatic patients. Therefore, some scholars advocate early release before irreversible neurological symptoms appear13. In conclusion, intramedullary lipoma management should be based on the patient's individual condition. The basic information about patients, types of potential disease, complications, and whether compression symptoms had occurred were included. However, choosing subtotal resection rather than total resection has reached a consensus.
In this case, the clinical symptoms and imaging findings of intramedullary lipoma and syringomyelia are similar, but their management is different. To avoid iatrogenic injury caused by misdiagnosis, attention should be paid to the differentiation of the two, to ensure a better quality of life for patients after surgery.