Epidural cavernous hemangioma misdiagnosed as a schwannoma: A case report

Abstract

A woman in her early 50s presented with an 8-month history of bilateral lower limb weakness and a 3-month history of unsteady gait. Imaging revealed a dumbbell-shaped mass near T1–T3, initially diagnosed as a schwannoma. Intraoperatively, a highly vascular dark red tumor was discovered, and only partial resection was performed due to bleeding risk. Pathology confirmed an epidural cavernous hemangioma. Symptoms had significantly improved at the 2-month follow-up without recurrence. This case highlights the importance of comprehensive preoperative imaging to prevent misdiagnosis and optimize surgical planning for atypically located tumors.

Background

Epidural cavernous hemangioma is a rare benign vascular malformation ¹ ; it is a non-neoplastic lesion that typically originates from the vertebral body. Cavernous hemangiomas arising outside the vertebral body and without bone involvement are even rarer, accounting for only 4% of all epidural tumors. ² Due to their characteristic dumbbell shape and tendency to invade the neural foramen, these tumors are often misdiagnosed. ³ Although they are benign tumors, if not treated in a timely manner, their slow growth can lead to significant neurological impairment. Only a few studies have reported the imaging characteristics and management of nonvertebral epidural cavernous hemangiomas. ⁴ Herein, we present a unique case of a nonvertebral, pure epidural cavernous hemangioma that was misdiagnosed as a schwannoma, with the aim of providing a reference for the diagnosis and management of this rare lesion.

Case report

A woman in her early 50s presented to Quzhou People’s Hospital in April 2025 with an 8-month history of bilateral lower limb weakness and a 3-month history of unsteady gait. Based on physical examination, the muscle strength in both lower limbs was graded at 4/5. Laboratory tests showed no abnormalities. Chest computed tomography (CT) (Figure 1(a) to (d)) revealed a soft tissue mass with a density similar to that of muscle at the level of T1–T3 vertebrae and left paravertebral area, measuring approximately 4.6 cm ×3.7 cm × 3.9 cm, with a CT value of approximately 30 HU. The left neural foramen was enlarged. Chest spine magnetic resonance imaging (MRI) (Figure 2(a) to (i)) showed a slightly low signal on T1-weighted imaging (T1WI) and a high signal on T2-weighted imaging (T2WI) in the mass located at the T1–T3 vertebral level, with uniform signal intensity and clear boundaries. The mass showed uniform and significant enhancement on post-contrast imaging, with a size of approximately 4.2 cm × 5.6 cm × 3.6 cm. Based on these findings, an imaging diagnosis of a neurogenic tumor, most likely a schwannoma, was considered preoperatively. However, we did not perform vascular imaging (CTA/MRA/DSA) preoperatively because, according to our clinical protocol, CT and MRI results are considered adequate for surgical planning.

Figure 1.

(a–d) CT images of the patient. The lesion is indicated by the red arrow at the T1–T3 vertebral level. (a and b) Lung window: These views illustrate the extra-spinal extension of the tumor into the thoracic cavity, causing mass effect on the left apical lung, which underscores the importance of CT in evaluating the full anterior–posterior dimension of the lesion. (c and d) Mediastinal window: The tumor causes enlargement of the intervertebral foramen and extends into the spinal canal through the foramen, presenting as a dumbbell-shaped mass and (e) image of the pathology report (H&E, 200×). CT: computed tomography; H&E: hematoxylin and eosin.

Figure 2.

MRI results of the patient (The lesion is indicated by the red arrow, at the T1–T3 vertebral level.). (a and b) Sagittal T1-weighted imaging (T1WI) shows a tumor located in the epidural space of the spinal canal and in the paraspinal region, exhibiting homogeneous low signal intensity. (c, d, and e) Fat-suppressed (FS) T2-weighted sagittal sequences demonstrate the lesion within the spinal canal to be fusiform (spindle-shaped), extending in a craniocaudal (superior–inferior) direction. (f and g) Sagittal post-contrast T1WI shows marked, homogeneous enhancement. The tumor extends with finger-like (pseudopodial) projections into the ipsilateral intervertebral foramen, which is widened; it traverses the foramen into the spinal canal, producing a dumbbell-shaped appearance. (h and i) Axial post-contrast T1WI demonstrates the lesion eccentrically encasing the spinal cord in a semicircular (crescentic) fashion within the canal. MRI: magnetic resonance imaging.

Written informed consent for the treatment procedure was obtained from the patient before treatment initiation. During the surgical procedure, after successful anesthesia induction, a skin incision was made, followed by dissection of the subcutaneous fat and muscle layers to expose the spinous processes. The muscles on both sides of the spinous processes were retracted to fully expose the T1–T3 vertebrae. After achieving hemostasis, a bilateral laminectomy of the T2 vertebra was performed, which revealed a dark red epidural tumor, accompanied with significant bleeding. The total intraoperative blood loss was approximately 300 mL. Intraoperatively, a vascular tumor was suspected. Given the difficulty in controlling bleeding from the tumor, we decided to temporarily leave the tumor in the thoracic cavity and complete the resection of the intradural tumor. The tumor in the thoracic cavity was left undisturbed. Hemostatic measures included electrocautery applied to the tumor’s upper and lower poles and bilateral sides, followed by dissection toward the anterior side of the spinal canal to dissect and sever the tumor. After complete removal of the intradural tumor, hemostasis was achieved using sterile gauze (Ethicon LLC, Johnson & Johnson company, Somerville, New Jersey, USA). 2082 hemostatic gauze was applied for hemostasis. The foraminal tumor was cauterized, and after removing the hemostatic materials, thorough irrigation was performed to ensure that there was no further bleeding before reapplication of the 2082 gauze and spraying of hemostatic gelatin to enhance hemostasis. Postoperative biopsy confirmed the diagnosis of cavernous hemangioma (Figure 1(e)). Immunohistochemistry results were as follows: Ki67 (+5%), ERG (+), CD34 (+), CD31 (+), PR (−), SSTR2 (−), and EMA (−).

Two months postoperatively, follow-up CT and MRI (Figure 3) showed that the tumor in the thoracic cavity was still present, while the intradural tumor had been completely resected. The patient exhibited good postoperative recovery, with significant improvement in lower limb weakness and walking instability. The patient was advised to continue to visit for regular follow-ups.

Figure 3.

(a–b) Postoperative follow-up CT images obtained 2 months after surgery. (c–d) Postoperative follow-up MRI images obtained 2 months after surgery. The lesion is indicated by the red arrow. The images demonstrate that the tumor within the spinal canal was surgically resected to alleviate symptoms of spinal cord compression. CT: computed tomography; MRI: magnetic resonance imaging.

The reporting of this study conforms to the Case Report (CARE) guidelines. ⁵ Written informed consent was obtained from the patient to publish their anonymized data. The study received ethical exemption from the Ethics Committee of Quzhou People’s Hospital (No. 2025-079). We have deidentified all patient details.

Discussion

Cavernous hemangioma is a tumor-like congenital vascular malformation with an unclear etiology. Based on its location, it can be classified into four types: ⁶ intramedullary (Type I), intradural extramedullary (Type II), epidural (Type III), and vertebral (Type IV). Epidural cavernous hemangioma is considered a Type III vascular tumor. Histologically, the lesions are characterized by severely dilated vascular spaces lined with a layer of endothelium, lack of mature vascular wall structures, and features of chronic hemorrhage in the adjacent tissue. ⁷ It is commonly accompanied with bleeding, calcification, and hemosiderin deposition. This condition primarily affects the posterior thoracic spinal canal, which may be related to the relatively large epidural space in the thoracic spine and the lower resistance in the posterior thoracic spinal canal.^8,9 Cavernous hemangiomas most commonly occur among individuals aged 30–60 years, ³ with women being affected in approximately 70% of the cases.^6,10 The pathogenesis of cavernous hemangiomas is not fully understood. Although some researchers have historically suggested a link to defects in the migration and differentiation of the primitive mesoderm, ¹¹ recent evidence increasingly points to the role of acquired somatic mutations in genes related to vascular endothelial integrity as a key mechanism in sporadic cases.^12,13 Our patient’s negative family history strongly supports this sporadic pathogenesis, aligning with the hypothesis that these malformations arise from postzygotic vascular endothelial defects rather than inherited genetic mutations. ¹⁴ Factors such as excessive physical activity, anticoagulant therapy, pregnancy, trauma, and radiation can induce the development of this disease.^15,16 Cavernous hemangioma is thus considered either familial or sporadic. ¹⁴ The patient in this case had no family history of similar conditions or genetic history, further corroborating a sporadic occurrence.

The main clinical manifestations of epidural cavernous hemangioma include sensory deficits and radicular pain below the affected spinal level, resulting from compression of the spinal cord or nerve roots. Despite its slow growth, acute symptoms have also been reported, ¹⁷ often attributed to spontaneous hemorrhage within the tumor leading to acute spinal cord compression. Although rare, this can lead to irreversible neurological damage if it occurs, which requires urgent attention. In this case, the patient’s bilateral lower limb weakness persisted and gradually worsened.

In the present case, the preoperative diagnosis was neurogenic tumor; however, due to a misdiagnosis, intraoperatively, the tumor was found to have abundant vascular supply and was large in size, making it impossible to achieve complete resection. Thus, the decision to perform partial resection of the intradural tumor was taken. This preoperative misdiagnosis significantly impacted patient outcome. The analysis of the misdiagnosis is as follows: CT scan and cross-sectional enhanced T1WI showed the tumor growing into the neural foramen, causing an enlargement of the foramen with a “dumbbell-shaped” appearance, which is characteristic of a neurogenic tumor. Cavernous hemangiomas typically grow along the long axis of the spinal canal in a fusiform shape with pointed ends, presenting a spindle or conical shape on sagittal views.^6,16 On cross-sectional images, they may show a characteristic lobulated contour, compressing and surrounding the spinal cord,^1,15 suggesting a nodular and plastic growth. Due to their composition of malformed vascular structures, their CT value is lower and similar to that of large blood vessels. This tumor shape is consistent with that of a typical neurogenic tumor but differs from the typical appearance of a cavernous hemangioma.

After reviewing the postoperative imaging data, the following imaging features can help distinguish a neurogenic tumor from a cavernous hemangioma:^6,18,19 1. On T1WI, the epidural fat is compressed, showing displacement anteriorly and inferiorly. On coronal-enhanced images, the dura mater is compressed and shifted to the right, showing linear enhancement at the upper and lower margins, suggesting that the tumor is located in the epidural space. Epidural tumors are more commonly vascular tumors, whereas neurogenic tumors are typically located subdurally. 2. On T2WI, cavernous hemangiomas usually show high signal intensity, while neurogenic tumors display slightly higher signal intensity. This signal difference is significant for accurate imaging diagnosis. 3. On enhanced scans, cavernous hemangiomas typically show significant enhancement, with a greater degree of enhancement than neurogenic tumors, aiding further distinction between the two types of lesions. The T2WI signal and enhancement characteristics in this case were more consistent with the diagnosis of cavernous hemangioma. To further substantiate this distinction through objective measures, quantitative MRI analysis was performed. Although both schwannomas and cavernous hemangiomas may appear qualitatively as T1WI-hypointense, T2WI-hyperintense, and enhancing masses, quantitative analysis reveals subtle yet critical differences. As summarized in Table 1, the quantitative parameters in our case—specifically, a T2WI signal intensity ratio of 2.8 and an enhancement percentage of 265%—fall within the characteristic range for cavernous hemangiomas and are distinct from those typical of schwannomas. This quantitative profile aligns with the underlying pathology: cavernous hemangiomas, composed of massively dilated, slow-flowing vascular channels, exhibit extremely high T2WI signal and intense enhancement, whereas the compact architecture of Schwann cells and collagen fibers in schwannomas results in more moderate T2WI signal and enhancement. Thus, the quantitative MRI parameters provide objective evidence supporting the diagnosis of cavernous hemangioma over that of schwannoma, significantly strengthening the validity of the imaging-based differential diagnosis. 4. Neurogenic tumors often present with necrosis and cystic degeneration, and calcification is relatively rare. In contrast, cavernous hemangiomas are commonly associated with intratumoral hemorrhage, calcification, or hemosiderin deposition around the tumor. When hemorrhage occurs, corresponding high signals can be seen on both T1WI and T2WI. In this patient, there was no intratumoral hemorrhage, calcification, or hemosiderin deposition, making misdiagnosis more likely.

Table 1.

Quantitative MRI parameters for differential diagnosis of spinal epidural masses.

Parameter	Current case	Typical cavernous hemangioma6,18,19	Typical schwannoma20–23
T1WI signal intensity ratio a	1.1	0.9–1.2	0.7–0.9
T2WI signal intensity ratio a	2.8	2.0–3.0	1.5–2.2
Enhancement percentage (%) b	265%	150%–300%	80%–150%

a

Calculated as lesion signal intensity divided by spinal cord signal intensity.

b

Calculated as (post-contrast signal intensity − pre-contrast signal intensity)/pre-contrast signal intensity × 100%

MRI: magnetic resonance imaging; T1WI: T1-weighted imaging; T2WI: T2-weighted imaging.

In the differential diagnosis of spinal hypervascular lesions, other vascular tumors such as hemangioblastomas and capillary hemangiomas must also be considered. Unlike the cavernous hemangioma presented in our case, central nervous system hemangioblastomas, although also hypervascular, are typically characterized by associated prominent cystic changes and often exhibit more intense enhancement of the mural nodules.^24,25 Furthermore, capillary hemangiomas are usually smaller in size and demonstrate homogeneous nodular enhancement; however, their T2WI signal intensity is generally less pronounced than that of cavernous hemangiomas, and they less frequently cause the extensive bony remodeling or mass effect observed in our case.^26,27 The imaging features of our case—homogeneous high T2WI signal, absence of cystic components, and a diffuse epidural growth pattern—are more aligned with a classic cavernous hemangioma, thereby aiding its distinction from other vascular tumors.

Due to the differences in treatment strategies, which can significantly affect the prognosis, cavernous hemangiomas need to be differentiated from hematogenous metastatic tumors and lymphoma. The key points in differential diagnosis are as follows: 1. Hematogenous metastatic tumors usually occur in middle-aged and older patients, with a history of primary malignant tumors such as lung or breast cancer. They often involve multiple spinal regions, including the vertebral bodies and spinal cord. Spinal lymphoma is more commonly a secondary malignant disease, frequently involving the vertebral bone, with lymphomatous lesions found in other parts of the body. Hematogenous metastatic tumors and lymphoma are often associated with bone destruction. In contrast, cavernous hemangiomas typically do not cause bone destruction, although they can lead to neural foramen enlargement. ¹⁸ 2. On MRI, ²⁸ cavernous hemangiomas have distinct features compared with hematogenous metastatic tumors and lymphoma, particularly on T2WI and enhanced scans. The signal intensity of cavernous hemangiomas is usually much higher than that of the other two types. Furthermore, cavernous hemangiomas are commonly associated with hemorrhage, which exhibits characteristic signal abnormalities, further aiding their distinction from other lesions. By integrating these imaging features, a more accurate diagnosis of cavernous hemangioma can be established, misdiagnosis as other tumor types can be prevented, and a targeted treatment plan can be formulated.

The best treatment for cavernous hemangioma is complete surgical resection to prevent the risk of rebleeding and progressive neurological deterioration. ² According to the literature,^2,29,30 even in cases of recurrent lesions, complete resection has shown to achieve complete recovery of neurological function and pain relief at the long-term follow-up. Patients with incomplete tumor resection can still achieve favorable clinical outcomes, with 80% of patients experiencing complete improvement in neurological status and 60% experiencing pain relief. Therefore, good preoperative neurological function is often associated with good clinical outcomes. However, when complete resection is not achieved, the risk of bleeding and tumor recurrence exists. Existing literature recommends a follow-up duration of 6–12 months to adequately assess residual tumor progression and facilitate long-term neurological recovery. Consequently, the 2-month follow-up in our case represents a limitation, and a longer observation period is necessary to evaluate the ultimate outcome. Postoperative radiotherapy serves as an effective adjunct for tumors that are not fully excised. Nonetheless, stereotactic radiotherapy (hypofractionated dose of 32 Gy in 4 fractions) may be considered, given that traditional radiotherapy is not widely employed due to the potential risk of spinal cord radiation damage.^1,14,18,31 In this case, due to the preoperative misdiagnosis and the large portion of the tumor outside the neural foramen, which posed a high risk of significant intraoperative bleeding, the surgery had to be aborted midway. This resulted in a significant loss and regret for the patient. Therefore, the tumor’s extension into the anterior and neural foramen areas significantly limits complete resection, especially when the tumor’s portion outside the neural foramen is large. This highlights the criticality of accurate preoperative diagnosis and careful surgical planning to ensure complete tumor resection and minimize surgical risks.

In summary, for spinal tumors affecting the neural foramen, the most likely and common diagnosis is neurogenic tumors. However, epidural cavernous hemangioma, as a rare tumor, should be included in the differential diagnosis, especially at the cervical and upper thoracic spinal levels. Epidural cavernous hemangiomas have specific imaging features; they are typically located in the epidural space and often appear in a fusiform shape, with intratumoral hemorrhage, calcification, or hemosiderin deposition. Therefore, a careful review of preoperative imaging data can enable accurate preoperative differential diagnosis and help prevent intraoperative bleeding and the risk of persistent neurological damage.