Angiolipomas are usually found in the subcutaneous tissue of the trunk and limbs. Spinal angiolipomas (SALs) are uncommon and have rarely been reported. We report a series of nine SALs patients who received surgical treatment in our department. To summarize the clinical characteristics of SALs, propose our surgical strategies, and evaluate the effects of the operation.
This was a retrospective review of nine SALs patients who received surgical treatment from August 2015 to March 2020. Total or subtotal resection was determined by the axial localization (dorsal or ventral) and the extent of intervertebral foramen involvement. The outcomes were assessed based on the modified Japanese Orthopaedic Association (mJOA) scoring system utilized before surgery and at various follow-up points.
Among the nine patients, the mean mJOA score before surgery was 6.6±2.3, compared with 10.1±1.1 at the last follow-up time point (33.4±11.8 months). All patients achieved good outcomes, even in cases of subtotal resection.
Early surgical resection of SALs is recommended, and the specific procedures should be determined by the axial localization (dorsal or ventral) and the extent of intervertebral foramen involvement. Most of the patients had a good prognosis, even in cases of subtotal resection.
Angiolipomas are benign tumors composed of mature fatty tissue and abnormal vascular elements, and they are usually found in the subcutaneous tissue of the trunk and limbs [
This study was approved by the Ethics Committee of Beijing Tsinghua Changgung Hospital (18013-0-01). This type of study does not require informed consent.
Nine patients with SALs (confirmed by final pathological results) were retrospectively reviewed at our center from August 2015 to March 2020. Those patients included four males and five females aged 12–73 years (46.6±17.9 years). The mean disease duration (history before diagnosis) was 15.1±19.1 months (range, 2–60), and the SALs locations included thoracic segments (n=5), lumbar segments (n=3), and cervical segments (n=1). Regarding the clinical symptoms, the patients’ complaints were mostly sensory disorders (numbness, paresthesia, and pain), motor deficits (limb weakness) and sphincter disturbances. None of the patients underwent invasive treatment before the operation. The patients’ general information is listed in
According to the classification methods proposed by Lin and Lin [
Electrophysiological monitoring, including somatosensory-evoked potentials and motor-evoked potentials, was used during every operation. The operations were performed with the patient in a semiprone position and with a posterior midline incision. The vertebral laminae of the corresponding lesion segments were removed to provide adequate exposure of the tumors.
In cases with a dorsal location and those in which the intervertebral foramens were not seriously affected, total resection of the tumors and the capsule was achievable. On the other hand, if the tumors had a ventral location or if the intervertebral foramens were seriously affected, wider resection was performed.
After resection of the tumors, the laminae were replaced and fixed with plates and screws to reconstruct the stability of the spine. Radiotherapy and chemotherapy were not administered after routine surgery, even in cases of subtotal resection.
The tumors were examined by two independent experienced pathologists after the surgery.
The outcomes were assessed based on the modified Japanese Orthopaedic Association (mJOA) scoring system before and 3, 6, and 12 months after the surgery and then once every 12 months. The mean follow-up period was 33.4±11.8 months (range, 21–54).
Data are expressed as the mean±standard deviation. The mJOA scores before and after surgery were compared using t-test. All statistical analyses were performed using SPSS (version 17.0; SPSS Inc., Chicago, IL, USA), and
Among the nine patients analyzed, the mJOA score was 6.6±2.3 before surgery and 10.1±1.1 at the last follow-up time point (
According to the histological examination, the tissue was composed of mature lipocytes and abnormal blood vessels, consistent with a diagnosis of angiolipoma (
Immunohistochemistry was performed in seven patients. The main results were CD31 (+), 6/7; CD34 (+), 6/7; S-100 (+), 5/7; Ki-67 (+), 4/7, <3%.
SALs were first reported by Berenbruch in 1890 [
As reported in previous studies, SALs are considered benign and rare lesions of the spinal axis, and they account for 0.14–1.2% of all spinal tumors and 2–3% of epidural spinal tumors [
The thoracic predominance of SALs was also found in our series of patients (5/9). This could be explained by the regional variation of the blood supply in the mid-thoracic spine, where the spine is least perfused. This may allow spinal lipomas to transform into SALs because of neovascularization caused by possible ischemic events [
We also noted some differences in our series. 1) We had a 12-year-old cervical SALs (C4–C6) patient (No. 7) with a relatively short disease duration (2 months). This situation has also been reported in other studies [
The clinical syndromes of epidural angiolipomas are basically the same as those of other benign space-occupying spinal tumors [
Sudden deterioration of neurological symptoms can occur due to intratumoral hemorrhage or thrombosis [
Lin and Lin [
Si et al. [
Histologically, SALs are tumors composed of mature lipocytes and proliferating abnormal vessels, including capillary, sinusoidal, venous or arterial vascular elements. The ratio of fat to vessels is variable, ranging from 1 : 3 to 2 : 3 [
The extent of resection for infiltrative SALs has always been a topic of debate. Because patients’ symptoms are caused by tumors in the spinal canal, surgeons generally do not deal with the affected vertebral bodies. Therefore, infiltration does not determine the choice of surgical procedure. In our opinion, the axial localization (dorsal or ventral) and the extent of intervertebral foramen involvement are the factors that should determine the surgical plan.
Most cases in which tumors are located dorsally and those in which the intervertebral foramens are not seriously affected can be totally resected. In such cases, we usually found that the tumors were compressive epidural fatty tissue intermingled with vascular structures that bled easily. Total resection was relatively easy to achieve without dura injury because adhesions between the tumors and the dura were limited.
However, if tumors are located ventrally, if the intervertebral foramens are seriously affected, or if the thoracic cavity is involved, wider resection should be planned. The extent of laminectomy should be appropriately expanded, especially on the symptomatic side. Additionally, according to Si et al. [
According to the literature, most SALs patients have a good prognosis, even in cases of subtotal resection [
In our group, six cases (including two infiltrating SALs) achieved improved outcome rather than recovered. It may be related to the nerve root invasion by the tumor, the duration of symptoms and the timing of surgery. As to recurrence, all seven patients who underwent total tumor resection had good prognoses with a mean follow-up of 30.6 months, and there was no recurrence. The patient who underwent subtotal resection (patient No. 1) exhibited an improved outcome 54 months after the surgery, which was a relatively long follow-up period, with no obvious signs of recurrence. From our point of view, early surgical resection is recommended because of the improvement or recovery of symptoms after surgery and the extremely low recurrence rate.
SALs are rare but well-defined benign tumors. In addition to clinical characteristics and radiological manifestations, the diagnosis of SALs depends strongly on pathological findings. Early surgical resection is recommended, and the specific procedures used should be determined by the axial localization (dorsal or ventral) and the extent of intervertebral foramen involvement. Most patients have a good prognosis, even in cases of subtotal resection.
No potential conflict of interest relevant to this article was reported.
This type of study does not require informed consent.
Conceptualization : XZ, GW
Data curation : SD, GW, HZ
Formal analysis : XZ, SD, GW, HZ
Funding acquisition : JJW, GW
Methodology : XZ, SD
Project administration : XZ, JJW, GW
Visualization : XZ, JJW
Writing - original draft : XZ, SD
Writing - review & editing : JJW, GW
This work was supported by the Beijing Tsinghua Changgung Hospital Fund (Grant No. 12017C1026).
A-D : It presents the magnetic resonance imaging (MRI) scans of patient No. 4. The dorsally located epidural mass (T11–T12) was isointense on T1-weighted images (WI), hyperintense on T2WI, and homogeneously enhanced on contrast-enhanced images. E-H : It presents the MRI scans of patient No. 1. The mass was located in the ventral part, and the vertebral body (L5) and right intervertebral foramen were also affected. The mass and the affected vertebral body were hypointense on T1WI, hyperintense on T2WI, and inhomogeneously enhanced on contrast-enhanced images. A and E : Sagittal T1WI. B and F : Sagittal T2WI. C and G : Sagittal contrast-enhanced image. D and H : Axial contrast-enhanced image.
A and B : It presents the postoperative the magnetic resonance imaging (MRI) scans (2 years after surgery) of patient No. 4. MRI shows that the tumors were completely removed without recurrence. C-F : It presents the postoperative MRI (1 month and 4 years after surgery) scans of patient No. 1. The results show that the tumors were partially removed, and there was no sign of further growth. A : Sagittal T2WI. B : Axial T2WI. C : Sagittal T2WI 1 month after surgery. D : Axial T2WI 1 month after surgery. E : Sagittal T2WI 4 years after surgery. F : Axial T2WI 4 years after surgery.
A : Intraoperative photo. The tumors were mainly composed of adipose tissue mixed with vascular structures that easily bled. B : Photomicrograph. The tumor was composed of mature adipose tissue and proliferating vascular elements (H&E, original magnification ×40).
Patients’ general information
No. | Sex/age | Symptom | Disease duration (months) | Level | Axial localization | Infiltration | Preop/postop mJOA score | Follow-up duration (months) | Evolution |
---|---|---|---|---|---|---|---|---|---|
1 | M/67 | Weakness in both legs (severe on the right side) | 24 | L5 | Ventral and RIF | Yes | 8/11 | 54 | Improved |
2 | F/47 | Thoracic back pain; diminished position sensation of left leg; slight sphincter disturbance | 4 | T6–T8 | Dorsal and BIF | No | 6/11 | 50 | Recovered |
3 | F/45 | Paresthesia in left leg; weakness in both legs; slight sphincter disturbance | 2 | T6–T7 | Dorsal and BIF | No | 6/10 | 36 | Improved |
4 | F/37 | Numbness and pain in both legs | 60 | T11–T12 | Dorsal | No | 9/11 | 34 | Recovered |
5 | M/36 | Numbness, paresthesia and pain in both legs; slight sphincter disturbance | 12 | T8–T10 | Dorsal and RIF | Yes | 8/10 | 33 | Improved |
6 | F/54 | Thoracic back pain | 2 | T4–T6 | Dorsal and BIF | No | 9/11 | 26 | Recovered |
7 | M/12 | Weakness and numbness in both legs; slight sphincter disturbance | 2 | C4–C6 | Dorsal | No | 3/10 | 25 | Improved |
8 | M/48 | Paresthesia and pain in right leg | 6 | L1–S3 | Dorsal and BIF | No | 7/9 | 22 | Improved |
9 | F/73 | Numbness and pain in right leg; weakness in both legs; sphincter disturbance | 24 | L3–L5 | Dorsal and RIF | No | 3/8 | 21 | Improved |
mJOA : modified Japanese Orthopaedic Association, M : male, RIF : right intervertebral foramen, F : female, BIF : bilateral intervertebral foramen
A comparison with the published single center report on treatment and outcomes of SALs
Study | N | Age (years) | Duration (months) | Resection | Radiotherapy | Evolution | Complications | Recurrence | Follow-up time | |
---|---|---|---|---|---|---|---|---|---|---|
Wang et al. [ |
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Infiltrating | 2 | 50.0±5.7 | 17.5±5.0 | 2 sub-total resection | No | 1 recovery, 1 improve. | No | No | 40 months | |
Noninfiltrating | 10 | 47.6±5.5 | 16.4±8.3 | 10 total resection | No | 5 recovery, 5 improve. | No | No | From 3 to 192 months | |
Bouali et al. [ |
||||||||||
Infiltrating | 0 | |||||||||
Noninfiltrating | 9 | 51.1±11.8 | 10.9±7.9 | 9 total removal | No | 9 recovery | No | No | NA | |
Si et al. [ |
||||||||||
Infiltrating | 3 | 56.7±8.4 | 126.7±202.2 | 3 total removal | No | Recovery rate : from 75% to 100% | No | No | Approximately 10 years | |
Noninfiltrating | 18 | 51.6±14.2 | 15.6±14.2 | 18 total removal | No | Recovery rate : from 50% to 100% | No | No | ||
This study | ||||||||||
Infiltrating | 2 | 51.5±21.9 | 18.0±8.5 | 2 sub-total resection | No | 2 improve | No | No | 33 and 54 months | |
Noninfiltrating | 7 | 48.6±12.5 | 14.3±21.6 | 7 total resection | No | 3 recovery, 4 improve | No | No | From 21 to 50 months |
SALs : spinal angiolipomas, NA : not available