Gross Total Resection of a Ventral Enterogenous Cyst of the Thoracic Spinal Cord: Case Report and Literature Review

Abstract

BACKGROUND AND IMPORTANCE:

Intraspinal enterogenous cysts, also referred to as neuroenteric cysts, represent a rare congenital disorder. As reported, these cysts are predominantly located in the cervicothoracic region, while being infrequently found in the lumbosacral region. Most patients manifest symptoms such as progressive local pain, signs of myelopathy, or radicular symptoms. Complete surgical resection of this disease is challenging. In the event of cyst fluid leakage during surgery, postoperative aseptic inflammation is likely to occur.

CLINICAL PRESENTATION:

We report a case in which an enterogenous cyst located ventral to the thoracic spinal cord was completely excised surgically without aspirating the cyst fluid. In addition, a comprehensive literature review and analysis are presented.

CONCLUSION:

Complete gross resection of a ventral thoracic spinal enterogenous cyst is feasible, avoiding cyst fluid aspiration to minimize aseptic meningitis risk. Complete resection is critical for reducing recurrence and postoperative rehabilitation.

ABBREVIATION:

ECs

enterogenous cysts.

Enterogenous cysts (ECs) are uncommon congenital and developmental malformation cysts. This disorder was first reported in 1928¹ and officially named in 1958.² This disease has a predilection for adolescent boys.³ The pathological process progresses slowly; however, these cysts are typically closely associated with the spinal cord or arachnoid.⁴ As a result, achieving complete surgical resection is often challenging, and postoperative complications are relatively common.⁵ We report a case of an enterogenous cyst on the ventral side of the lower thoracic spinal cord. In this case, the lesion was completely resected without aspirating the cyst fluid during the operation, and no additional surgical complications ensued. Through a comprehensive review of the existing literature, we discuss the surgical treatment experiences and relevant characteristics of this disease.

CLINICAL PRESENTATION

The Institutional Review Board of Beijing Tsinghua Changgung Hospital approved this study. The necessary patient informed consent was obtained in this study. A 57-year-old woman presented with 1 month of progressive bilateral leg weakness, numbness, pain, and urinary dysfunction. On admission, she had an indwelling catheter. Left lower limb muscle strength was grade 1 in proximal and distal muscle groups; right side was grade 2. Hypotonia, hyperreflexia, and bilateral Babinski signs were present. MRI showed a ventral subdural lesion at T9-T10 with hypointense T1-weighted imaging and hyperintense T2-weighted imaging signals, matching cerebrospinal fluid (Figure 1A-1C). Axial imaging revealed the “spinal cord embedding sign,” suggesting an enterogenous cyst. Preoperative tests (electrocardiogram, chest x-ray, blood count, liver and kidney function) showed no surgical contraindications. The lesion was resected by a posterior midline approach. To prevent cyst fluid leakage and aseptic meningitis, the cyst was removed intact without aspiration. After general anesthesia and prone positioning, a midline incision was made at T9-T10. The surgical procedure (Figure 2A-2F) proceeded as follows: An ultrasonic bone scalpel was used for partial laminectomy. Hemostasis was achieved with gelatin matrix and bipolar coagulation. Under microscopy, the dura was opened and suspended. The cyst—grayish-white, soft, encapsulated, and well-defined—was found ventral to and embedded within the spinal cord, with firm adhesions. Microsurgical dissection separated it from neural tissue. The intramedullary base was carefully freed. En bloc resection was completed. After hemostasis, the dural defect was repaired with synthetic graft and anti-adhesion patch. The lamina was reconstructed with titanium plates. A drainage tube was placed extradurally. Layers were closed. Postoperatively, she received mannitol, methylprednisolone, and antibiotics. One week later, MRI confirmed complete resection with no residual or recurrent lesion (Figure 3A-3C). Histopathology confirmed enterogenous cyst (Figure 4A and 4B). Two weeks postsurgery, leg strength remained unchanged (grade 2), but bladder and bowel function improved. She started hyperbaric oxygen therapy and passive rehab. Active strengthening began at 1 month. At 3 months, right leg strength reached grade 4, left grade 5. She walked independently with crutches. MRI showed no recurrence (Figure 5A-5C).

FIGURE 1.

The postoperative MRI of the lesion. MRI revealed a space-occupying lesion ventral to the spinal cord within the subdural space at the levels of the ninth and 10th thoracic vertebrae. A, The lesion presented as a hypointense signal on T1-weighted imaging. B and C, The lesion presented as a hyperintense signal on T2-weighted imaging, similar to the signal intensity of cerebrospinal fluid.

FIGURE 2.

Intraoperative findings during the operation. A, The lesion was exposed by a posterior median approach. B, The spinal cord was retracted and suspended to the contralateral soft tissues through a posterolateral approach. C, The adhesions between the lesion and the ventral spinal cord were carefully dissected using sharp dissection techniques to the greatest extent possible. D, Bipolar electrocautery forceps were used for hemostasis when necessary. E, Eventually, the cyst was completely excised without rupture. F, After the complete removal of the cyst, no significant bleeding or damage was evident on the ventral surface of the spinal cord.

FIGURE 3.

The follow-up MRI 1 week after the surgery. A and C, MRI T2-weighted imaging indicated that the lesion had been completely excised, with no signs of recurrence or residual lesions.

FIGURE 4.

The postoperative pathological examination of the lesion. A and B, The postoperative pathological examination confirmed the diagnosis of an enterogenous cyst.

FIGURE 5.

The MRI After 3 months of the surgery showed no signs of recurrence or residual lesions. A, The MRI T1-weighted imaging. B, The MRI T2-weighted imaging. C, Axial MRI T2-weighted imaging.

DISCUSSION

ECs, or neurenteric cysts, are rare congenital malformations lined with gastrointestinal or respiratory epithelium that secretes mucus.⁶ They mainly affect men, especially children and young adults, and usually occur ventrally in the subdural space of the lower cervical and upper thoracic spinal cord. Lumbosacral involvement is very rare.^4,7,8 This case, a middle-aged to elderly woman with a cyst on the ventral lower thoracic spine, is atypical in both age and location. The exact cause of ECs is still unclear.

Generally, they are thought to arise from abnormal endodermal development during early embryogenesis, often linked to remnants of the neurenteric duct—a temporary structure connecting the amnion and yolk sac in the third week of gestation.⁵ Persistent adhesions between endoderm and notochord or ectoderm may impair notochord development, leading to cyst formation and conditions such as diastematomyelia.⁹ ECs often occur with other congenital defects of the spine, spinal cord, or gut.¹⁰ Some researchers propose that misplaced cysts form when endodermal tissue migrates dorsally through mesodermal openings into the neural tube during the third embryonic week.^11,12

ECs typically cause radicular symptoms or spinal cord compression at the lesion level.¹³ Most patients start with limb weakness, followed by sensory changes, pain, and sphincter dysfunction.^14,15 Rarely, cyst fluid leakage into the subarachnoid space can cause fever and fluctuating neurological decline resembling myelitis.^16,17 MRI is the preferred imaging method. These cysts are usually round or ovoid with clear borders. On T1-weighted imaging, they seem slightly hypointense; on T2-weighted imaging, they are hyperintense, similar to cerebrospinal fluid.^9,18-20 They typically show no enhancement on contrast MRI, although some show irregular rim enhancement because of inflammatory or fibrovascular tissue in the wall.⁶ Axial and sagittal MRI often shows the cyst extending into the spinal cord, producing the “spinal cord embedding sign,” which helps assess embedding depth and compression severity.¹ In this case, the lesion is near-round, ventrally located, well-defined, and compresses the spinal cord. Despite these features, preoperative diagnosis is difficult, with accuracy under 30%.²¹ Main differentials include dermoid, epidermoid, arachnoid, and ependymal cysts, distinguished by histopathology.^13,22,23 Final diagnosis depends on postoperative pathology.²⁰

Complete surgical resection is the preferred treatment of ECs. However, total resection rates remain below 40% because of the ventral spinal location of most cysts, which makes surgery technically difficult.¹² These cysts often adhere tightly to the pia mater or arachnoid, and aggressive removal may worsen or cause neurological deficits.^24-26 Surgical options include anterior, lateral, and posterior approaches, with most cases using posterior midline laminectomy for lateral access to the spinal cord.²⁷ In this case, we removed the cyst completely without aspirating its fluid. After opening the dura and draining cerebrospinal fluid, cottonoids and gelatin sponges were placed above and below the lesion to protect neural tissue and prevent cyst rupture and fluid leakage into the subarachnoid space. When needed, part of the dentate ligament was cut, and the spinal cord was gently suspended to the opposite side to rotate it slightly, improving exposure to the ventral cyst and expanding the surgical space. The cyst wall was dissected sharply, with minimal use of bipolar cautery to avoid thermal damage. The cyst was removed intact, with no spillage. After resection, the cavity was rinsed with corticosteroids and warm saline to reduce inflammation. Complete resection is possible with careful technique. When safe, surgeons should aim for total removal while avoiding cyst fluid leakage, to lower the risk of recurrence and complications and improve long-term outcomes.

Most of the patients with ECs have a favorable prognosis.⁵ The recurrence rate is relatively low after complete resection. Partial resection may lead to recurrence, in which case reoperation can be considered, and the overall prognosis remains good.²⁸

CONCLUSION

Complete gross resection of a ventral thoracic spinal enterogenous cyst is feasible with meticulous microsurgical techniques, avoiding cyst fluid aspiration to minimize aseptic meningitis risk. This approach, combined with intraoperative spinal cord suspension and dural reconstruction, yielded favorable outcomes without neurological deterioration. Postoperative rehabilitation and short-term follow-up demonstrated significant motor recovery and no recurrence. This case highlights the importance of tailored surgical strategies and multidisciplinary collaboration in managing rare spinal congenital anomalies.

Funding

The case report was funded by the National Key Research and Development Program of China (2024YFC3405300; 2024YFC3405304); Beijing Natural Science Foundation (L246072; 7244448).

Disclosures

The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.