https://orcid.org/0000-0002-0574-029X
Abstract
Intradural spinal lipomas without associated dysraphism are rare, and the optimal surgical strategy remains controversial, particularly for thoracic lesions strongly adhered to neural structures. A 17-year-old female presented with progressive spastic gait and sensory disturbances in the lower extremities that developed during pregnancy. Magnetic resonance imaging showed an intradural lesion at the T5–T8 level consistent with a spinal lipoma. Because of the absence of a clear dissection plane and strong adhesion to neural elements, tumor resection was not attempted. Instead, decompression and duraplasty were performed. The patient showed gradual neurological improvement and was discharged 5 weeks postoperatively. At the 30-year follow-up, the patient remained neurologically stable with no evidence of tumor progression. Decompression without tumor resection may provide favorable long-term outcomes in selected cases of non-dysraphic intradural spinal lipomas with strong adhesion to neural structures.
Introduction
Intradural spinal lipomas are rare lesions that are mostly associated with spinal dysraphism in the lumbosacral region [1]. Meanwhile, non-dysraphic intradural lipomas are uncommon and may occur in younger individuals. They often occur in the thoracic spine with progressive neurological deficits [2–4]. Symptom exacerbation during pregnancy has also been reported, which suggests that physiological factors may affect the clinical course [5].
While surgical intervention is generally indicated for patients with progressive neurological symptoms [3, 6], the optimal surgical strategy remains controversial. Although aggressive tumor resection has been advocated for maximal decompression, the risk of neurological injury is substantial in some cases. This is due to the absence of a clear dissection plane and frequent incorporation of neural elements within the lesion [7, 8]. Function-preserving strategies, including limited decompression and duraplasty without tumor resection, have been proposed. However, the long-term durability and safety of such approaches remain insufficiently characterized.
Whether decompression without tumor debulking can provide sustained neurological stability over extended follow-up in patients with dense adhesions to neural structures remains unclear. Herein, we report a rare case of non-dysraphic thoracic intradural spinal lipoma treated with decompression and duraplasty without tumor resection, which showed stable neurological outcomes over 30 years of follow-up.
Case report
A 17-year-old pregnant female presented with a 2-month history of abnormal sensation in the plantar aspect of both feet during ambulation. Although the symptoms were initially expected to resolve after delivery, they persisted postpartum, prompting consultation at a local clinic. Magnetic resonance imaging (MRI) showed a suspected spinal tumor, for which the patient was referred to our institution for further evaluation.
Neurological examination showed a spastic gait without motor weakness in the lower extremities. Sensory testing indicated decreased light touch and pain sensation below the T10 level. Deep tendon reflexes, including the patellar and Achilles tendon reflexes, were hyperactive bilaterally. Bilateral ankle clonus was also present. No bladder or bowel dysfunctions were observed. MRI indicated an intradural lesion extending from T5 to T8, with high signal intensity on both T1- and T2-weighted imaging, consistent with a lipomatous lesion (Fig. 1).
Preoperative MRI showing a dorsal thoracic spinal mass; sagittal T1-weighted (a) and T2-weighted (b) magnetic resonance images indicate a longitudinally extensive hyperintense mass in the dorsal spinal canal extending from T5 to T8; the lesion compresses the thoracic spinal cord from the dorsal side and displaces it anteriorly.
Myelography showed a complete block of contrast flow at the corresponding level. The patient underwent a laminectomy from T4 to T9. Intraoperative ultrasonography, along with direct visualization, indicated indistinct tumor margins with no identifiable cleavage plane between the lesion and the neural tissue (Fig. 2).
Intraoperative ultrasound findings of the dorsal thoracic lipomatous lesion; sagittal intraoperative ultrasound images obtained from the cranial (a) and caudal (b) sides of the lesion show a hyperechoic lipomatous mass dorsal to the spinal cord; the integrated schematic illustration (c) shows the extent of the lesion beneath the dura mater and its close anatomical relationship with the spinal cord; the tumor–spinal cord interface was partially indistinct.
Dural opening showed a yellowish mass consistent with a lipoma within the intradural space (Fig. 3). The arachnoid membrane was thickened and densely adherent to the lesion. Neural elements, including nerve roots, were incorporated within the tumor. Given the absence of a safe dissection plane and the high neurological injury risk, tumor debulking, or resection was not attempted. Decompression with duraplasty was performed using a fascia lata graft of ~1.5 × 10 cm (Fig. 4).
Operative findings showing intimate adhesion between the lipomatous lesion and neural structures; after dural opening, the lipomatous lesion was tightly adherent to the dorsal aspect of the spinal cord (a); the schematic illustration summarizes the operative findings, showing nerve roots incorporated within the lesion and a poorly demarcated tumor–cord interface (b).
Expansile duraplasty following decompression of the intradural lipomatous lesion; following decompression of the lesion, expansile duraplasty was performed using an autologous fascial graft as a dural patch (a); the schematic illustration depicts the surgical concept of partial decompression combined with dural expansion using a fascia lata graft measuring 1.5 × 10.0 cm, increasing the intradural space around the compressed spinal cord (b).
Histopathological examination confirmed the lipoma diagnosis. Postoperatively, the patient showed gradual improvement in sensory disturbance and spastic gait and was discharged 5 weeks post-surgery. The patient has since received annual follow-up checks. At the latest (30 years), the patient had remained neurologically stable without symptom recurrence. Serial MRIs showed no evidence of tumor progression (Fig. 5).
Serial postoperative MRI demonstrates long-term stability of the residual lipomatous lesion; magnetic resonance images obtained 5, 10, 23, and 30 years postoperatively demonstrate long-term radiographic stability; sagittal images are shown in the upper row, and corresponding axial images are shown in the lower row; there was no evidence of progressive enlargement of the residual lesion or increased compression of the spinal cord during the 30-year follow-up period.
Discussion
Observations
This case was characterized by the absence of a clear dissection plane and the incorporation of neural elements within the lesion. Therefore, partial tumor resection was potentially hazardous. The non-resection strategy resulted in a stable neurological status without tumor progression over 30 years.
Spinal lipomas are congenital malformations classified as closed spinal dysraphisms and are most commonly encountered in the lumbosacral region [3]. Intradural spinal lipomas without associated dysraphic anomalies are rare [9]. Unlike dysraphic lipomas, these non-dysraphic lesions may arise in the thoracic spine [10].
Non-dysraphic intradural spinal lipomas are characterized by their intradural location and close association with neural structures. Unlike dysraphic lipomas, these lesions often lack a clear anatomical plane of separation from the spinal cord. This makes surgical intervention technically demanding and increases the risk of neurological injury [6, 11].
The optimal surgical strategy for non-dysraphic intradural spinal lipomas remains controversial. Historically, complete or aggressive resection was often performed, yielding favorable outcomes through adequate decompression and prevention of further neurological deterioration [6, 8]. However, due to the intimate adhesion between the lipoma and neural tissue, the risk of iatrogenic neurological injury with this approach is high [12]. Although favorable outcomes with limited surgical approaches, including decompression, partial debulking, and duraplasty, have been described [10, 13], even partial debulking may pose a considerable risk when the tumor is tightly adherent to the spinal cord and neural elements are incorporated into the lesion. Here, a non-resection strategy focusing solely on decompression may be more appropriate. While surgical strategies focusing on decompression and duraplasty without tumor removal, with symptomatic improvement without neurological deterioration, have been described, these reports are limited. The long-term durability of such non-resection strategies remains unclear.
Lessons
In selected patients, a non-resection approach may represent a viable long-term management option. However, this is a single case report, and the indication for a non-resection strategy should be determined carefully based on intraoperative findings. This includes the presence or absence of a safe dissection plane and the degree of neural incorporation.
In selected cases with non-dysraphic intradural spinal lipomas strongly adhering to neural structures, decompression without tumor resection may be a suitable surgical option, with the potential for favorable long-term outcomes.
Acknowledgements
The authors thank the patient for her continued cooperation throughout the long-term clinical and radiological follow-up. We also acknowledge the medical staff involved in her treatment and longitudinal care.
Conflicts of interest
None declared.
Funding
None declared.
