Abstract
Background Spinal angiolipomas (SALs) are uncommon benign lesions that may present insidiously with back pain or acutely with weakness due to tumor bleeding/thrombosis. Given their rarity, these lesions are often overlooked in the differential diagnosis of epidural masses. The purpose of this article is to report the case of an epidural SAL and to conduct a literature review on the topic.
Methods A case report and review of the literature using the PubMed/Medline databases. All case reports and case series were reviewed up to June 2015.
Results A 65-year old female presented with neurogenic claudication and magnetic resonance imaging (MRI) revealed lumbar spinal stenosis. Following decompressive surgery, she experienced symptom resolution, but three months postoperatively she presented to the emergency department with acute paraparesis. A thoracic MRI revealed a lesion located between T8 and T10 causing severe spinal cord compression. Following emergent laminectomy and en bloc resection, the patient regained function and the lesion was diagnosed as SAL. Our literature review revealed 178 reported cases, with a female and thoracic predominance. The majority of patients underwent surgical treatment, achieving a gross total resection in most cases. Similarly, complete symptom resolution was the most common outcome.
Conclusion Spinal angiolipomas are uncommon spinal tumors. However, they may be treated as any other space-occupying lesion, and surgical resection allows for complete symptom recovery in most patients.
Introduction
Spinal angiolipomas (SAL) are uncommon benign tumors composed of mature adipocytes and abnormal blood vessels. They comprise approximately 1.2% of all spinal axis tumors, and 3% of all spinal epidural neoplasms.1 Given their rarity, these lesions are often overlooked in the differential diagnosis of space-occupying lesions within the spinal canal. Though they most commonly have an insidious course, in some cases the initial manifestation is acute paraplegia.2–6
Nonetheless, piecemeal excision is achieved in most of these cases, and spinal cord decompression leads to symptom recovery in the majority of patients.1 Thus, the purpose of this article is to report on a case of epidural SAL with co-existing lumbar spinal stenosis and to conduct a literature review on the topic.
Case Report
A 65-year old female with body mass index of 29 kg/m2 presented with a 6-week history of lower extremity dysesthesia and neurogenic claudication. On physical examination, she had a positive straight leg test at 30 degrees, and reflexes were diminished in both lower extremities; she was neurologically intact. Magnetic resonance imaging (MRI) revealed significant lumbar spinal stenosis at L4/L5 and L5/S1 (Figure 1). Following failure of conservative therapy, she underwent an uneventful L4-S1 bilateral laminoforaminotomy.
Magnetic resonance image showing lumbar spinal stenosis. Sagittal (A) and axial (B) T2-weighted images showing lumbar spinal stenosis at L4/L5 secondary to ligamentum flavum hypertrophy and bilateral facet arthropathy. Sagittal (C) and axial (D) T2-weighted images showing foraminal stenosis on the left secondary to facet arthropathy at L5/S1.
The patient experienced significant relief of her symptoms, but three months later she presented to the emergency department with acute onset of severe back pain and history of recent fall due to leg weakness. On physical examination she was hyperreflexic on both lower extremities, and her lower extremity strength was 3/5. A new MRI revealed a space-occupying lesion in the epidural space, causing significant compression on the spinal cord at the levels of T8 – T10 (Figure 2). Additionally, the lesion extended through the intervertebral foramen at T9/T10. The patient underwent an emergent posterior laminectomy and en bloc resection of a soft, reddish-brown tumor (Figure 3), followed by instrumentation from T7 – T11. Following surgery, histopathological analysis was consistent with angiolipoma (Figure 4). Although the tumor extended through an intervertebral foramen, pathological analysis of surrounding soft tissues revealed no infiltration. The patient underwent an uneventful recovery, and is symptomfree and without evidence of tumor recurrence 6 months after surgery.
Magnetic resonance image showing an epidural lesion extending from T8 – T10. Sagittal (A) and axial (B) T1-weighted images showing the dumbbell-shaped hyperintense lesion extending multiple levels and through the foramen at T9/T10. Additionally, the lesion shows hypointense regions, corresponding to the vascular component of the tumor. Sagittal (C) and axial (D) T2-weighted images showing severe spinal stenosis with spinal cord compression.
Intraoperative photographs showing a reddish-brown lesion overlying the thecal sac (Left) which was removed en bloc following laminectomy (Right).
Tumor specimen consisting of a soft, reddish-brown mass (Left). Histological slide showing mature adipocytes and blood vessels of various sizes, some filled with thrombin (Right).
Literature Review
A digital search of the PubMed/Medline databases was performed using the algorithm [(“spine” OR “spinal”) AND “angiolipoma”] up to June 2015. Article titles and abstracts were then individually screened to identify potential articles of interest, and selected manuscripts were recorded in a digital database. Article references were also utilized to identify other case reports/case series to reduce publication bias.
A total of 107 articles reporting on 177 patients (108 articles and 178 patients with the present case) with epidural SALs were identified (Table 1).1–107 The average age for all patients (including the present case) was 46 ± 16 years, with a range of 17 months to 85 years. From the total group, 105 (59%) patients were female. The most common presenting symptom was paraparesis in 54 (30.3%) patients, followed by thoracic/low back pain in 43 (24.2%) patients. The range of time with symptoms before presentation was from a few minutes (acute onset) to 30 years in one patient.105
Review of published cases on epidural spinal angiolipoma.
The majority of tumors were located in the thoracic spine (131 patients; 73.6%), followed by the lumbosacral spine in 30 patients (16.9%), cervicothoracic and thoraco-lumbar in 6 patients each (6.8% combined) and the cervical spine in only 4 cases (2.3%).10, 35, 105 Tumors were most commonly located posteriorly in the axial plane. Based on the classification by Lin & Lin,108 only 25 (14%) tumors were found to be infiltrating in nature. The majority of patients underwent surgery, and experienced complete symptom recovery. Recurrences were uncommon, and have been reported in only two occasions (1.1%).23, 69
Discussion
Angiolipomas are histologically benign tumors that most commonly occur in subcutaneous tissue in the forearms, trunk, neck, and proximal upper extremities.109 Occurrence within the spinal canal is uncommon, but when it occurs it is most commonly in the epidural space.1 Histologically, these lesions consist of “mature adipocytes and branching capillary-sized vessels, which usually contain fibrin thrombi.”109 Some studies have also performed immunohistochemical staining, showing positivity for CD31, Factor XIIIa, and Factor VIII.84 Some believe SALs originate from pluripotential mesenchymal stem cells,12 but others argue they most likely represent a “congenital malformation or a benign hamartoma”1 or that they arise from primitive mesenchyme.70
SALs resemble other space-occupying lesions in terms of symptoms, and most patients present with a history of thoracic/low back pain and progressive lower extremity weakness. However, paraparesis or paraplegia may also occur acutely, particularly in the setting of tumor bleeding or thrombosis.2–6, 65, 96 A presumed diagnosis can be usually made by MRI, although the ultimate diagnosis is made with biopsy. Lesions typically appear hyperintense on non-contrast T1-weighted images due to their fatty content.110 Additionally, there may be hypointense regions on T1-weighted images, which represent the vascular component of the tumor. Thus, these regions will be enhancing after contrast administration.110 Computed tomography scans are less frequently utilized, but may show tumor calcification,63, 73 vertebral body trab ecula tion,14, 72 and/or vertebral bo dy erosion.73 Though most SALs are found in the epidural space (as mentioned previously), there have been several reports of intradural (including intramedullary) locations.111–116
Historically, SALs have been classified as non-infiltrating and infiltrating,108 with the latter referring to tumoral infiltration into the vertebral body and/or adjacent soft tissues. In the present review, only 13.4% of tumors were found to be infiltrating in nature. More recently, Si et al. proposed another classification system based on tumor characteristics observed on MRI. This group of authors described three tumor types: Type IA (intraspinal tumor without lipomatosis), Type IB (intraspinal tumor with lipomatosis above and below the tumor) and Type II (dumbbell-shaped tumor).105 The rationale behind this classification was that Type IB tumors occur more frequently in obese patients and are more challenging from a surgical standpoint owing to the extensive associated epidural lipomatosis.105 In contrast, Type IA tumors are more easily resectable, and Type II represent the most complex type of tumor that may warrant additional internal fixation.105
Treatment of SALs is surgical, which was performed in 168 out of 178 patients (94.4%) in the present review. Additionally, adjuvant radiation therapy was used in three cases (1.7%) due to suspicion of malignancy.13, 17, 46 Gross total resection was achieved in most cases, but in a subset of patients (particularly those with infiltrating tumors) only subtotal resection was achieved.69 Of seven reported cases of intradural/intramedullary SALs, complete excision was only achieved in one,113 and most patients only experienced partial improvement in symptoms. When examining global outcomes, we found that the majority of patients experience complete symptom resolution, even for patients presenting acutely with paraplegia.
The case described in this article represented a distinctive challenge given the initial presentation with neurogenic claudication and concomitant finding of lumbar spinal stenosis. Additionally, the acute pre-sentation of paraparesis suggested tumoral thrombosis or bleeding, as it has been reported in other cases.65, 96 Fortunately, following decompression and piecemeal excision, the patient was able to regain full strength postoperatively.
While screening the entire spinal column (with MRI) in cases of suspected lumbar spinal stenosis is not common practice, there may be several indications for cervicothoracic spine screening. Paraparesis without other signs/symptoms of cauda equina syndrome is rarely due to lumbar stenosis, and may be due to myelopathy and/or other neurological diseases. Patients who present with signs/symptoms of stenosis but with other concomitant findings such as hyperreflexia or spastic gait may require cervico-thoracic spine screening to rule-out spinal cord compression or disease. Lastly, though occurrence of multiple SALs in the same patient has been reported, it is unusual (only 2 cases in the present literature review).10, 63 Each case should be individualized, and a thorough history and physical exam should dictate whether a patient requires cervical, thoracic, and/or lumbar spine imaging.
Conclusion
SALs are infrequent entities that mimic other space-occupying lesions within the spinal canal. Though not common, they should be included in the differential diagnoses of epidural tumors, given the excellent outcome that may be achieved in most patients.
Disclosures
The authors have no conflict of interests or funding sources to declare.
- Copyright © 2015 ISASS - This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery
References
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