Spinal epidural lipomatosis: report of a case secondary to hypothyroidism and review of literature

Role of epidural fat in the local milieu: what we know and what we don't

PURPOSE

Traditionally, the epidural fat (EF) is known as a physical buffer for the dural sac against the force and a lubricant facilitating the relative motion of the latter on the osseous spine. Along with the development of the studies on EF, controversies still exist on vital questions, such as the underlying mechanism of the spinal epidural lipomatosis. Meanwhile, the scattered and fragmented researches hinder the global insight into the seemingly dispensable tissue.

METHODS

Herein, we reviewed literature on the EF and its derivatives to elucidate the dynamic change and complex function of EF in the local milieu, especially at the pathophysiological conditions. We start with an introduction to EF and the current pathogenic landscape, emphasizing the interlink between the EF and adjacent structures. We generally categorize the major pathological changes of the EF into hypertrophy, atrophy, and inflammation.

RESULTS AND CONCLUSIONS

It is acknowledged that not only the EF (or its cellular components) may be influenced by various endogenic/exogenic and focal/systematic stimuli, but the adjacent structures can also in turn be affected by the EF, which may be a hidden pathogenic clue for specific spinal disease. Meanwhile, the unrevealed sections, which are also the directions the future research, are proposed according to the objective result and rational inference. Further effort should be taken to reveal the underlying mechanism and develop novel therapeutic pathways for the relevant diseases.

A case of spinal epidural lipomatosis presenting as a stroke mimic

Here we present the case of a patient with right upper extremity and right lower extremity weakness of a three-day duration, which triggered a stroke evaluation. Ultimately, the diagnosis of spinal epidural lipomatosis (SEL) was made. Non-stroke diagnoses that present with stroke-like symptoms are referred to in the medical literature as stroke mimics. Such cases present with neurological deficits that imitate acute ischemic stroke. The frequency of such presentations occurs in up to 30% of initially suspected stroke. This case illustrates that SEL can present as a stroke mimic. To our knowledge, this is the first description of a presentation in the medical literature of SEL as a stroke mimic.

Could Spinal Epidural Lipomatosis Be the Hallmark of Metabolic Syndrome on the Spine? A Literature Review with Emphasis on Etiology

Spinal epidural lipomatosis is defined by an excessive amount of epidural fat in the spinal canal, usually in the lumbosacral tract: a well-known cause of lumbar pain and spinal stenosis with a possible wide range of neurological symptoms. Recent research data reveal that, nowadays, obesity has become the main cause of spinal epidural lipomatosis. Moreover, this condition was recently recognized as a previously unknown manifestation of metabolic syndrome. Radiological studies (CT and MRI) are the only tools that are able to diagnose the disease non-invasively. Indeed, radiologists play a key role in disease recognition, with subsequent possible implications on patients' systemic health assessments. Despite its clinical importance, the condition is still underreported and neglected. The current literature review summarizes all the main etiologies of spinal epidural lipomatosis, particularly regarding its linkage with metabolic syndrome. An overview of disease characteristics from diagnosis to treatment strategies is also provided.

Clinical and radiological characteristics of spinal epidural lipomatosis: A retrospective review of 90 consecutive patients

Background

The epidemiology and clinical characteristics of spinal epidural lipomatosis (SEL) have been well-reported in the literature. However, few studies investigated the concomitant spinal pathologies that were present in patients with SEL. Therefore, we aimed to summarize the clinical and radiological characteristics of patients with SEL diagnosed on spinal imaging.

Methods

Patients who were diagnosed with SEL on magnetic resonance imaging from January 2018 to October 2020 at our institution were included in the study. Clinical data was collected using a standardized data collection form. SEL was graded using a modified version of the Borré grading system. Factors associated with moderate or severe SEL were determined using multiple logistic regression.

Results

A total of 90 patients were included in the analysis. The mean (±SD) age was 59.3 (±17.1) years, and 62 patients (68.9%) were male. 61 patients (67.8%) had moderate or severe SEL. Most patients were overweight or obese (57 patients, 63.3%). The most common presenting symptoms was back pain (57 patients, 63.3%). SEL was diagnosed incidentally in 42 patients (46.7%). The lumbar spine was the most common site of SEL (35 patients, 38.9%). The most common concomitant spinal pathologies were disc bulge (83 patients, 92.2%) and flavum hypertrophy (60 patients, 66.7%). Moderate or severe SEL was associated with WHO Obesity Class, back pain or radicular leg pain at first presentation, and SEL that was worst at the lumbar or lumbosacral spinal level.

Conclusions

Moderate or severe SEL were independently associated with WHO Obesity Class, back pain, radicular leg pain, and SEL that was worst at the lumbar or lumbosacral spinal level. Future studies should prospectively evaluate whether weight loss therapy is warranted in patients with SEL.

Spinal epidural lipomatosis: a rare and frequently unrecognized complication of Cushing syndrome

CONTEXT

Spinal Epidural Lipomatosis (SEL) is a rare and frequently unrecognized complication of Cushing syndrome (CS). Only nine previous cases of SEL have been described in CS. Here, we present a case of severe SEL and review the literature.

CASE REPORT

A 29-year-old man who had severe CS secondary to an ACTH-secreting pituitary macroadenoma. He presented with progressive lower limb weakness over a 2-year period leading to complete paraplegia in the last 4 months. In addition, he had classic symptoms and signs of severe CS. His evaluation confirmed the diagnosis of CS with a 4-fold increase in his daily free urinary cortisol (1190 mg/day), a positive 1-mg dexamethasone suppression test (AM cortisol 729 nmol/l) and an elevated ACTH of 196 ng/dl (10-65). Magnetic resonance imaging (MRI) revealed a 20-mm pituitary adenoma and extensive fat accumulation in the spinal canal extending from C7 to S5 with significant spinal cord compression from T2-T10. The patient underwent an urgent spinal cord decompression surgery. He showed an immediate improvement and was able to walk with crutches 3 weeks later and independently 3 months later. About 13 days after the spinal surgery, he underwent a trans-sphenoidal surgery resulting in eucortisolemia.

CONCLUSION

SEL is a rare and serious complication of CS. It should be considered in any patient with CS, especially when there is neurological symptoms or disproportionate weakness of the lower limbs. Its management should be individualized but prompt surgical decompression should be considered even in patients with relatively long history of paraparesis.

A New Subform? Fast-Progressing, Severe Neurological Deterioration Caused by Spinal Epidural Lipomatosis

Spinal epidural lipomatosis (SEL) is a rare condition caused by hypertrophic growth of epidural fat. The prevalence of SEL in the Western world is approximately 1 in 40 patients and is likely to increase due to current medical and socio-economic developments. Rarely, SEL can lead to rapid severe neurological deterioration. The pathophysiology, optimal treatment, and outcome of these patients remain unclear. This study aims to widen current knowledge about this “SEL subform” and to improve its clinical management. A systematic literature review according to the PRISMA guidelines using PubMed, Scopus, Web of Science, and Cochrane Library was used to identify publications before 7 November 2021 reporting on acute/rapidly progressing, severe SEL. The final analysis comprised 12 patients with acute, severe SEL. The majority of the patients were male (9/12) and multimorbid (10/12). SEL mainly affected the thoracic part of the spinal cord (11/12), extending a median number of 7 spinal levels (range: 4–19). Surgery was the only chosen therapy (11/12), except for one critically ill patient. Regarding the outcome, half of the patients regained independence (6/11; = modified McCormick Scale ≤ II). Acute, severe SEL is a rare condition, mainly affecting multimorbid patients. The prognosis is poor in nearly 50% of the patients, even with maximum therapy. Further research is needed to stratify patients for conservative or surgical treatment.

MRI Features and Clinical Significance of Spinal Epidural Lipomatosis: All You Should Know

Spinal epidural lipomatosis (SEL) is defined as the abnormal accumulation of unencapsulated adipose tissue in the spinal epidural space. SEL can be asymptomatic or can cause a wide range of symptoms, the most common of which is neurogenic claudication. Several other neurological manifestations may also occur, above all myelopathy and radicular symptoms. The spinal level most frequently involved in patients with SEL is the lumbar one, followed by the thoracic one. Imaging plays a key role in disease assessment. MRI is considered the most effective and sensitive modality for diagnosing and staging SEL. Anyway, also CT scan can diagnose SEL. The diagnosis may be incidental (in mild-moderate disease) or may be taken into account in cases with neurological symptoms (in moderate-severe disease). There are some recognized risk factors for SEL, the most common of which are exogenous steroid use and obesity. Recent studies have found an association between SEL and obesity, hyperlipidemia and liver fat deposition. As a matter of fact, SEL can be considered the spinal hallmark of metabolic syndrome. Risk factors control represents the initial treatment strategy in patients with SEL (e.g. weight loss, steroid therapy suspension). Surgical decompression may be required when conservative treatment fails or when the patient develops acute/severe neurological symptoms.

Clinical and imaging characteristics in patients undergoing surgery for lumbar epidural lipomatosis

Background

Lumbar epidural lipomatosis (LEL) is characterized by abnormal accumulation of unencapsulated adipose tissue in the spinal epidural space. Such accumulation compresses the dural sac and nerve roots, and results in various neurological findings. However, the pathophysiology of LEL remains unclear. This study examined the associations between imaging and clinical findings in detail, and investigated the mechanisms underlying symptom onset by measuring intraoperative epidural pressures in LEL.

Methods

Sixteen patients (all men; mean age, 68.8 years) were enrolled between 2011 and 2015. Mean body mass index was 26.5 kg/m². Four cases were steroid-induced, and the remaining 12 cases were idiopathic. All patients presented with neurological deficits in the lower extremities. Cauda equina syndrome (CES) alone was seen in 8 patients, radiculopathy alone in 4, and both radiculopathy and CES (mixed CES) in 4. All patients subsequently underwent laminectomy with epidural lipomatosis resection and were followed-up for more than 1 year. We investigated the clinical course and imaging and measured epidural pressures during surgery.

Results

Subjective symptoms improved within 1 week after surgery. Mean Japanese Orthopaedic Association (JOA) score was 15.2 ± 2.8 before surgery, improving to 25.4 ± 2.5 at 1 year after surgery. On magnetic resonance imaging, all lipomatosis lesions included the L4–5 level. On preoperative computed tomography, saucerization of the laminae was not observed in radiculopathy cases, whereas saucerization of the posterior vertebral body was observed in all radiculopathy or mixed CES cases. Intraoperative epidural pressures were significantly higher than preoperative subarachnoid pressures. The results suggest that high epidural pressure resulting from the proliferation of adipose tissue leads to saucerization of the lumbar spine and subsequent symptoms.

Conclusions

Clinical courses were satisfactory after laminectomy. In LEL, epidural pressure increases and symptoms develop through the abnormal proliferation of adipose tissue. Higher epidural pressures induce saucerization of the laminae and/or posterior vertebral body. Furthermore, the direction of proliferative adipose tissue (i.e., site of saucerization) might be related to the types of neurological symptoms.

The prevalence of spinal epidural lipomatosis on magnetic resonance imaging

BACKGROUND

Spinal epidural lipomatosis (SEL) refers to an excessive accumulation of fat within the epidural space. It can be idiopathic or secondary, resulting in significant morbidity. The prevalence of SEL, including idiopathic and secondary SEL, and its respective risk factors are poorly defined.

PURPOSE

We sought to: (1) assess the prevalence of SEL among patients who underwent a dedicated magnetic resonance imaging (MRI) scan of the spine-including incidental SEL (ie, SEL without any spine-related symptoms), SEL with spine-related symptoms, and symptomatic SEL (ie, with symptoms specific for SEL); and (2) assess factors associated with overall SEL and subgroups. In addition, we assessed differences between SEL subgroups.

METHODS

We reviewed the records of 28,902 patients, aged 18 years and older with a spine MRI (2004 to 2015) at two tertiary care centers. We identified SEL cases by searching radiology reports for SEL, including synonyms and misspellings. Prevalence numbers were calculated as a percentage of the total number of patients. We used multivariate logistic regression analysis to identify factors associated with overall SEL and subgroups.

RESULTS

The prevalence of overall SEL was 2.5% (731 of 28,902): incidental SEL, 0.6% (168 of 28,902); SEL with symptoms, 1.8% (526 of 28,902); and symptomatic SEL, 0.1% (37 of 28,902). Factors associated with overall SEL in multivariate analysis were the following: older age (odds ratio [OR]: 1.01, 95% confidence interval [CI]: 1.01-1.02, p<.001), higher modified Charlson comorbidity index (OR: 1.10, 95% CI: 1.07-1.13, p<.001), male sex (OR: 2.01, 95% CI: 1.71-2.37, p<.001), BMI>30 (OR: 2.59, 95% CI: 1.97-3.41, p<.001), Black/African American race (OR: 1.66, 95% CI: 1.24-2.23, p=.001), systemic corticosteroid use (OR: 2.59, 95% CI: 1.69-3.99, p<.001), and epidural corticosteroid injections (OR: 3.48, 95% CI: 2.82-4.30, p<.001).

CONCLUSIONS

We found that about 1 in 40 patients undergoing a spine MRI had SEL; 23% of whom with no symptoms, 72% with spine-related symptoms, and 5% with symptoms specific for SEL. Our data help identify patients who might warrant an increased index of suspicion for SEL.

Spinal epidural lipomatosis - an easily ignored secondary intraspinal disorder in spinal kyphotic deformities

Background

A previous study reported a high prevalence of spinal epidural lipomatosis (SEL) in patients with Scheuermann kyphosis (SK) and suggested that it may play a role in the pathogenesis of this disease. According to our observation, however, SEL occurs in other spinal kyphotic deformities as well. The aim of this study was to test the hypothesis that SEL commonly occurs in patients with different types of kyphotic deformities as a secondary intraspinal disorder.

Methods

MR images of 16 patients with congenital kyphosis (CK), 40 patients with SK, 13 patients with tuberculotic kyphosis (TK), and 69 age- and sex-matched controls were retrospectively evaluated. The body mass index (BMI), kyphosis Cobb angle, and sagittal diameters of spinal epidural fat (EF) and the dural sac (DS) in the apical region (EF_A, DS_A) and non-kyphotic region (EF_N, DS_N) were measured. The EF ratios at the apical vertebral level (EFR_A) and in the non-kyphotic region (EFR_N) were calculated as EF / (EF + DS).

Results

EF_A and EFR_A were significantly higher among patients with CK, SK, and TK than among controls (P < 0.05). Seven CK patients (43.8%), 8 SK patients (20.0%), and 11 TK patients (84.6%) fulfilled the diagnostic criteria for SEL, while only 6.3, 2.5, and 0% of patients in the control groups did (P = 0.019, 0.014, and < 0.001, respectively). Spearman’s correlation analysis showed statistically significant correlations between the kyphosis Cobb angle and the amount of EF in all three patient groups.

Conclusions

SEL is a common secondary intraspinal disorder in different types of kyphotic deformities, and surgeons should pay increased attention to this intraspinal anomaly because excessive EF may compress the spinal cord and cause neurological deficits.

[Spinal epidural lipomatosis as a rare side effect in steroid-dependent Jo-1 antibody syndrome]

Spinal epidural lipomatosis (SEL) of the thoracic and lumbar spine is a rare entity, which leads to compression of the spinal canal. The exact pathogenesis is still unknown. It most commonly occurs in patients with long-term exogenous or endogenous glucocorticoid excess or morbid obesity but there are also idiopathic forms. The symptoms depend on the severity of the SEL and can manifest as clinically asymptomatic, non-specific back pain, radiculopathy up to spinal cord compression. The diagnosis is usually achieved by magnetic resonance imaging (MRI) of the affected spinal segments. The treatment varies between discontinuation of glucocorticoids, weight reduction up to multisegmental decompressive laminectomy. The following case report presents the findings of SEL in a patient with steroid-dependent Jo-1 antibody syndrome and provides a current literature review on this rare disease.

Idiopathic Spinal Epidural Lipomatosis in the Lumbar Spine

Overgrowth of epidural fat, known as spinal epidural lipomatosis (SEL), can cause symptomatic compression of the spinal cord, conus medullaris, or cauda equina. Suggested predisposing factors such as obesity, steroid use, and diabetes mellitus have been based on a few reported cases, many of which were not surgically confirmed. There is a paucity of epidemiological data in surgically confirmed cases for this disorder. The purpose of this independently reviewed, retrospective, matched cohort analysis was to compare the demographics and incidence of comorbidities of patients who underwent lumbar decompression for SEL vs degenerative stenosis without SEL. Two surgeons' databases were reviewed to identify patients older than 18 years who underwent decompression surgery for magnetic resonance imaging-verified, symptomatic lumbar SEL. A matched control group comprised an equal number of patients with degenerative stenosis (n=14). Demographic data, body mass index, symptom type/duration, comorbidities, complications, treatment history, and associated pathology were collected from medical records. Previously suggested risk factors, such as obesity, endocrinopathy, and epidural steroid injections, were not significantly different between the SEL and control groups. Furthermore, there were no differences in operative times, complications, or blood loss. The only noted difference between the 2 groups was the preoperative duration of symptoms, on average double in patients with SEL. This series represents the largest of its kind reported to date. Because symptom duration was the only difference noted, it is postulated to be the result of lack of awareness of SEL. Future prospective study in a larger group of patients is warranted. [Orthopedics. 2016; 39(3):163-168.].

Unusual Spinal Epidural Lipomatosis and Lumbosacral Instability

Introduction. Epidural lipomatosis is most frequently observed in patients on chronic steroid treatment. Only a few idiopathic epidural lipomatosis cases have been described. Material and Methods. 64-year-old male patient presented with low back pain and left leg pain. Later, the patient experienced neurogenic claudication and radicular pain in the left leg without urinary dysfunction. Plain radiography and magnetic resonance imaging demonstrated an abnormal fat tissue overgrowth in the epidural space with compression of the dural sac, degenerative disc disease at L4-L5 level, and instability at L5-S1. Endocrinopathic diseases and chronic steroid therapy were excluded. If conservative treatment failed, surgical treatment can be indicated. Results. After surgery, there was a gradual improvement in symptoms and signs, and six months later the patient returned to daily activities and was neurologically normal. Conclusion. In the absence of common causes of neurogenic claudication, epidural lipomatosis should be considered. The standard test for the diagnosis of epidural lipomatosis is magnetic resonance (MR). At first, conservative treatment must be considered; weight loss and the suspension of prior corticosteroid therapy are indicated. In the presence of neurological impairment, the operative treatment of wide surgical decompression must be performed soon after diagnosis.

Cauda Equina Syndrome Caused by Idiopathic Epidural Lipomatosis

Spinal epidural lipomatosis (SEL) is a rare condition that presents as a back pain with progressive neurologic symptoms. Most affected patients are obese and receiving steroid therapy, or have an endocrinopathies. We report a rare case of cauda equina syndrome caused by SEL in a non-obese healthy young man without any evident traumatic episode. A healthy 19-year-old man, who had experienced lower back pain for two months, visited our emergency room because of the sudden development of motor weakness and voiding difficulty. Lumbar magnetic resonance image revealed extradural fat compressing the cauda equina. Urgent decompression via posterior laminectomy and excision of excess epidural fat resulted in an immediate symptom improvement.

[Spinal epidural lipomatosis]

Spinal epidural lipomatosis (SEL) is a rare condition affecting the thoracic and lumbar spine, characterized by a hypertrophy and hyperplasia of the rich vascularized fat tissue inside the spinal canal. The etiology of SEL is unknown. A high number of cases are associated with obesity, corticosteroid intake and a dysbalance in adrenocorticotropic hormone (ACTH)-cortisone metabolism. It can be an incidental radiographic finding or present with symptoms, such as low back pain, weakness of the lower limbs, dysesthesia, radiculopathy, claudication or even cauda equina syndrome. The interdisciplinary treatment consists of weight reduction, weaning from corticosteroids and in persisting cases or neurologic alterations in surgical decompression of the spinal canal. The following article presents a current review and a case report of this rare entity.

Idiopathic thoracic epidural lipomatosis with chest pain

Spinal epidural lipomatosis (SEL) is an overgrowth of the normally encapsulated adipose tissue in the epidural space around the spinal cord in the thoracic and lumbar spine causing compression of the neural components. Idiopathic SEL in non-obese patients is exceptional. Idiopathic SEL can result in thoracic myelopathy and lumbar radiculopathy. A thoracic radiculopathy due to idiopathic SEL has not been reported yet. We report a case of idiopathic SEL with intractable chest pain and paresthesia. We suggest that idiopathic SEL should be considered as a cause of chest pain.

Progressive epidural lipomatosis with steroid use in severe refractory asthma

BACKGROUND

Long-term immunosuppression with oral corticosteroids is frequently used to treat inflammatory diseases of the lung and is advocated in the management of some patients with asthma.

METHODS

The authors describe the case of a 35-year-old man with severe refractory asthma who developed a slowly progressive thoracic spinal cord syndrome.

RESULTS

Spinal imaging demonstrated the presence of spinal epidural lipomatosis, a rare complication of prolonged corticosteroid therapy, which is characterized by overgrowth of fat in the epidural space and neuronal compression.

CONCLUSIONS

Spinal epidural lipomatosis should be considered in patients receiving long-term corticosteroid therapy who develop symptoms and signs suggestive of spinal cord compression.

[Spinal cord compression caused by idiopathic dorsal epidural lipomatosis: Case report and critical review of the literature]

We report the case of a patient with spinal cord compression evolving over 36 months with spastic paraparesis. Anatomic imagery showed epidural lipomatosis. No predisposing factors were found. Surgical treatment was decided. A T1-T10 laminectomy with excision of the surplus epidural fat was performed. Immediate and medium-term postsurgical follow-up was favorable with the disappearance of the pyramidal syndrome. Other cases found in literature and the principal predisposing factors are discussed.

Decompression of idiopathic symptomatic epidural lipomatosis of the lumbar spine

Epidural lipomatosis has been implicated as a cause or contributor of symptomatic lumbar spinal stenosis. Symptomatic spinal epidural lipomatosis (SEL) of the lumbar spine is a rare disease, often associated with steroid overload. Idiopathic lipomatosis is even much less frequent. Signs and symptoms depend upon the level and degree of nerve root compression. Diagnosis is best based on MRI. Weight reduction can be curative, however, after failure of medical treatment or in severe cases surgical decompression should be performed. A 70-year-old man with both lower limb severe paresthesia and radicular symptoms unrelieved with conservative treatments such as medications and physical therapy was treated by surgical decompression. Obesity, endocrinopathic disease, and chronic steroid therapy were excluded. Interlaminar fenestration, lateral recess decompression and fat debulking were applied at all levels through the L2-S1. After surgery there was a gradual improvement in symptoms. We report a rare case of idiopathic SEL which has shown entire evolvement of lumbar spine with specific increase of radiological and clinical severity from L2-3 to L5-S1 in a non-obese patient.

Idiopathic spinal epidural lipomatosis

We report a rare case of paraparesis caused by thoracic spinal epidural lipomatosis in a female patient who did not have any recognized predisposing factor for this condition.

Myeloneuropathic presentation of spinal epidural lipomatosis

Spinal epidural lipomatosis (SEL) is accumulation of unencapsulated fat tissue within the epidural space of the spinal canal. The most common cause of SEL is corticosteroid therapy, whereas most of the non-corticosteroid-dependent cases are idiopathic. If unrecognized, it may result in diagnostic confusion with other neuropathic or myelopathic conditions. We report 2 cases of SEL. The first case is of a 30-year-old man who received corticosteroid therapy for an acute and probably immune-mediated demyelinating process. Subsequently, the addition of compressive effects of SEL resulted in diagnostic confusion and initial workup at other centers for spinal cord malignancy and vascular malformation. The patient's symptoms improved after decompression surgery. The second case is of a 63-year-old woman with a history of type 1 diabetes mellitus that presented with increasing numbness in the lower extremities. She was initially diagnosed with diabetic neuropathy; however, the presence of myelopathic signs led to further investigation and diagnosis of SEL. Decompression surgery resulted in improvement of symptoms.

Decompression of idiopathic lumbar epidural lipomatosis: diagnostic magnetic resonance imaging evaluation and review of the literature

Object

Idiopathic symptomatic spinal epidural lipomatosis (SEL) is a rare condition, and few reports have discussed diagnostic imaging criteria. To evaluate factors relating to its clinical symptoms, correlations between clinical features and the presence of spinal epidural fat were investigated, and the literature concerning idiopathic SEL was reviewed.

Methods

Morphological gradings of epidural fat were evaluated in seven patients with idiopathic SEL by using magnetic resonance (MR) imaging. In addition, body mass index (BMI), the number of involved vertebral levels, grade, and preoperative Japanese Orthopaedic Association (JOA) score were analyzed. Surgery resulted in symptomatic relief, with a mean JOA score recovery rate of 67.4%. Grading of epidural fat tended to display a slight negative correlation with preoperative JOA score, whereas a strong significant positive correlation was found between the number of involved vertebral levels and BMI.

Conclusions

The number of involved vertebral levels and obesity are strongly correlated, whereas severity of dural compression is not always significantly associated with neurological complications. These results indicate that epidural fat of the lumbar spine contributes to neurological deficits. In addition, weight-reduction therapy appears to decrease the number of vertebral levels involved. Magnetic resonance imaging–based grading is helpful for the diagnosis and evaluation of idiopathic lumbar SEL. Moreover, symptoms and neurological findings are important for determining the surgical approach.

Spinal epidural lipomatosis: case reports, literature review and meta-analysis

BACKGROUND CONTEXT

Symptomatic spinal epidural lipomatosis (SEL), a rare cause of spinal cord compression, has most often been associated with exogenous steroid use.

PURPOSE

Identify four associations with SEL, correlate the associated groups with level of disease and compare treatment with outcome data in these groups.

STUDY DESIGN/SETTING

Case reports of three patients and analysis of 104 cases from the literature.

PATIENT SAMPLE

Three patients from the senior author's practice.

OUTCOME MEASURES

Not applicable.

METHODS

The authors report three new cases of SEL not associated with steroid use. They review all available English literature and present a table of all 104 reported cases.

RESULTS

The clinical course of three new patients is reported.

CONCLUSIONS

Associated conditions are exogenous steroid use, obesity, endogenous steroid excess, and some remain idiopathic. Although SEL is a rare condition, our review of the literature reveals many more reported cases than previously thought. With increased awareness of this condition and improved imaging techniques, further studies of this disease should be undertaken.

Lumbosacral epidural lipomatosis: MRI grading

Lumbosacral epidural lipomatosis (LEL) is characterized by excessive deposition of epidural fat (EF). The purpose of our retrospective study was to quantify normal and pathologic amounts of EF in order to develop a reproducible MRI grading of LEL. In this study of 2528 patients (1095 men and 1433 women; age range 18-84 years, mean age 47.3 years) we performed a retrospective analysis of MRI exams. We obtained four linear measurements at the axial plane parallel and tangent to the superior end plate of S1 vertebral body: antero-posterior diameter of dural sac (A-Pd DuS), A-Pd of EF, located ventrally and dorsally to the DuS, and A-Pd of the spinal canal (Spi C). We calculated (a) DuS/EF index and (b) EF/Spi C index. We developed the following MRI grading of LEL: normal, grade 0: DuS/EF index >or=1.5, EF/Spi C index <or=40%; LEL grade I: DuS/EF index 1.49-1, EF/Spi C index 41-50% (mild EF overgrowth); LEL grade II: DuS/EF index 0.99-0.34, EF/Spi C index 51-74% (moderate EF overgrowth); LEL grade III: DuS/EF index <or=0.33, EF/Spi C index >or=75% (severe EF overgrowth). The MRI exams were evaluated independently by three readers. Intra- and interobserver reliabilities were obtained by calculating Kappa statistics. The MRI grading showed the following distribution: grade 0, 2003 patients (79.2%); LEL grade I, 308 patients (12.2%); LEL grade II, 165 patients (6.5%); and LEL grade III, 52 patients (2.1%). The kappa coefficients for intra- and interobserver agreement in a four-grade classification system were substantial to excellent: intraobserver, kappa range 0.79 [95% confidence interval (CI), 0.65-0.93] to 0.82 (95% CI, 0.70-0.95); interobserver, kappa range 0.76 (95% CI, 0.62-0.91) to 0.85 (95% CI, 0.73-0.97). In LEL grade I, there were no symptomatic cases due to fat hypertrophy. LEL grade II was symptomatic in only 24 cases (14.5%). In LEL grade III, all cases were symptomatic. A subgroup of 22 patients (42.3%) showed other substantial spinal pathologies (e.g., disk herniation). By means of simple reproducible measurements and indexes MRI grading enables a distinction between mild, moderate, and severe EF hypertrophy. Kappa statistics indicate that LEL can be reliably classified into a four-grade system by experienced observers.

Epidural lipomatosis secondary to indinavir in an HIV-positive patient

A human immunodeficiency virus-positive patient receiving indinavir therapy developed a slowly progressive paraparesis. Magnetic resonance imaging findings were consistent with epidural lipomatosis. On discontinuing indinavir, symptoms gradually remitted. Although indinavir, a protease inhibitor, is known to cause abnormal fat accumulation, to the best of our knowledge this is the first report of epidural lipomatosis.

Cauda equina syndrome secondary to idiopathic spinal epidural lipomatosis

STUDY DESIGN

Three cases of idiopathic epidural lipomatosis are reported.

OBJECTIVES

Description of the relationship between spinal pathologic overgrowth of fat tissue and neurologic symptoms.

SUMMARY OF BACKGROUND DATA

Idiopathic epidural lipomatosis is a very rare condition; it is usually secondary to chronic steroid therapy or endocrinopathic diseases.

METHODS

Three men with a mean age of 58.5 years, who experienced intermittent claudication, bilateral radicular pain in both legs, and urinary dysfunction with hypoesthesia in the perineal region, were evaluated by plain radiography and magnetic resonance imaging, the results of which demonstrated a pathologic overgrowth of fat tissue in the spinal canal with a marked impingement of the dural sac. Obesity, endocrinopathic diseases, and chronic steroid therapy were excluded for all patients. Surgical treatment was performed by wide multilevel laminectomies, fat debulking, and instrumented posterolateral fusion.

RESULTS

After surgery there was a gradual improvement in symptoms and signs so that 2 years later the patients returned to daily activities and were neurologically normal.

CONCLUSIONS

Spinal epidural lipomatosis can be a cause of back pain but rarely radicular impingement. Magnetic resonance imaging is the procedure of choice. The treatment must be performed early by wide surgical decompression.

Do glucocorticoids cause spinal epidural lipomatosis? When endocrinology and spinal surgery meet

Here, we report pathogenetic aspects of spinal epidural lipomatosis (SEL) based on a literature review. SEL is a rare entity but can cause significant morbidity. Its symptoms can be identical to those of more common disorders such as vertebral and disc disease, and cord lesions (for example, transverse myelitis, multiple sclerosis and syringomyelia). Therefore, it often goes undiagnosed. In addition, SEL occurs in patients on glucocorticoid therapy, which can lead to myopathy, thereby mimicking the motor symptoms of SEL. Glucocorticoids seem to play a major role in the development of SEL, although idiopathic SEL has also been reported. The latter occurs almost exclusively in obese individuals who may have concurrent hypercortisolism. Once clinically suspected, SEL is best diagnosed by magnetic resonance imaging (MRI). Treatment of SEL is directed at reducing body weight in patients with idiopathic SEL, and at decreasing glucocorticoid excess in patients with endogenous or exogenous hypercortisolism. In severe cases, decompressive laminectomy might become necessary to alleviate the neurological symptoms caused by spinal cord compression.

Ninety-degree rotation of the thoracic spinal thecal sac. Case report

This 44-year-old man presented with a 4-year history of progressive spastic weakness of his legs. He was found to have epidural lipomatosis behind the thoracic spinal cord, and the nerve roots exited from the posterior and anterior midline planes of the dura, indicating a 90 degree rotation of the thoracic cord. Magnetic resonance images clearly demonstrated the segmental thoracic nerve roots exiting from the dorsal midline of the dura, a finding confirmed at surgery. The authors found only one previously published case of rotation of the spinal cord. Directed mechanical stress caused by deformation of the rotated spinal cord, rather than compression from adipose tissue, is proposed as the mechanism of the myelopathy. The extent, location, and thickness of the associated extradural adipose tissue is suggestive of epidural lipomatosis. The lipomatous tissue might have been an epiphenomenon and cord rotation an isolated congenital anomaly. Alternatively, asymmetrical growth of epidural fat may have exerted torque, rotating the thecal sac.

Spinal epidural lipomatosis. Case report and review of the literature

Spinal epidural lipomatosis (SEL) is a condition in which excess adipose tissue is deposited circumferentially about the spinal cord in the epidural space. It is most frequently seen in patients on chronic glucocorticosteroid therapy for a variety of medical problems. This is a case report of lumbar epidural lipomatosis in a bodybuilder with radiculopathy supposedly induced by anabolic steroid intake.

Idiopathic spinal epidural lipomatosis

OBJECTIVE

Spinal epidural lipomatosis (SEDL) is a rare disorder often associated with the administration of exogenous steroids or the elevation of endogenous steroids. Spinal epidural lipomatosis develops in some patients in the absence of elevated steroid levels. The limited information known about idiopathic SEDL comes predominantly from isolated case reports. We proposed to study our experience with idiopathic SEDL and to review the literature.

METHODS

We identified eight symptomatic patients with idiopathic SEDL treated at our institution, which is the largest series reported. All patients were male and obese by body mass index (> 27.5 kg/m2). The mean age of the patients was 35.4 years. Idiopathic SEDL was equally distributed between the thoracic and lumbar spine. Six patients underwent laminectomy and fat debulking with good postoperative results; two patients were treated with a weight loss diet, which resulted in the relief of symptoms after losing > 15 kg each.

RESULTS AND CONCLUSION

A review of our patients in conjunction with other reported cases reveals the following: 1) idiopathic SEDL occurs almost exclusively in the obese population; 2) idiopathic SEDL seems to occur with equal frequency between the thoracic and lumber spine; 3) a strong male predominance exists; 4) thoracic SEDL presents at an earlier age compared with lumbar SEDL; 5) surgical decompression remains the treatment of choice for the immediate relief of symptoms. Our experience suggests that idiopathic epidural lipomatosis may be a pathological entity that has been underdiagnosed.

Neurogenic claudication by epidural lipomatosis: a case report and review of literature

Epidural lipomatosis is most frequently seen in patients on chronic steroid treatment. Only twelve cases of idiopathic spinal epidural lipomatosis have been described. In this report we present an additional case of this condition in a middle-aged male presenting with neurogenic claudication.

Idiopathic spinal extradural lipomatosis in a non-obese otherwise healthy man

Spinal extradural lipomatosis is rare and is usually associated with long-term steroid administration or obesity. It is most commonly thoracic in situation. We present a unique case of spinal extradural lipomatosis in a 20-year-old non-obese, clinically normal man. The role of MRI in investigation and the management options are discussed.

Idiopathic epidural lipomatosis as a cause of pain and neurological symptoms attributed initially to radiation damage

Epidural lipomatosis is a rare condition in which overgrowth of extradural fat can lead to back pain, spinal cord compression and radiculopathy. A 51-year-old man developed back pain and reduced mobility following a standard course of radiotherapy for a Stage I seminoma. His symptoms and radiological appearances were initially attributed to radiation fibrosis. Further investigations and operative intervention revealed epidural lipomatosis. The excess lipomatous tissue was removed with complete resolution of his symptoms.

Idiopathic and glucocorticoid-induced spinal epidural lipomatosis

Pathological overgrowth of the epidural fat in the spine has been described and reported nearly exclusively in patients either with Cushing's syndrome or on chronic intake of glucocorticoids for a variety of clinical disorders. The authors report four patients with documented spinal lipomatosis (three pathologically and one radiologically). Only one of these patients received corticosteroids, and none had an underlying endocrinological abnormality. All four patients were adult males with a mean age at onset of symptoms of 43 years (range from 18 to 60 years). The symptoms ranged from simple neurogenic claudication and radicular pain to frank myelopathy. Myelography followed by computerized tomography were instrumental in the diagnosis of the first three patients; the fourth was diagnosed by magnetic resonance imaging. The thoracic spine was involved in two cases and the lumbosacral area in the other two. The different treatment modalities were tailored according to the symptomatology of the patients. These included weight reduction of an overweight patient with minimal neurological findings in one case and decompressive laminectomy and fat debulking to achieve adequate cord decompression in the remaining three cases. Two patients improved significantly, the condition of one stabilized, and the fourth required a second decompression at other spinal levels. The various modalities of treatment and their potential complications are discussed.