Cavernous hemangiomas, in general, are rare benign vascular tumors of the central nervous system and may manifest throughout the nervous system, with a predilection for the cerebral cortex, cerebellum, and spinal tissue (1). Within the spine, these lesions are predominantly located in the vertebral body, constituting 5–12% of all spinal vascular pathologies, followed by occurrences in the intramedullary or extramedullary subdural spaces (2). PSECHs are particularly rare, with only approximately one hundred cases documented in the literature. The rate of preoperative misdiagnosis has been reported to be as high as 91.3% (2) (Table 1), with the literature indicating misdiagnosis rates of 78.57% (3), 88.89% (4), and 66.67% (5) in various studies. Inaccurate preoperative diagnoses can lead to various complications, such as misidentifying a tumor as blood seepage, resulting in its non-detection during surgery. Consequently, this study retrospectively analyzed published literature and the clinical data of seven patients with PSECHs in the Xiangyang Central Hospital Neurosurgery Department from January 2013 to November 2022, in order to enhance clinicians’ understanding of the disease and decrease preoperative misdiagnosis rates.

Cavernous hemangioma is a type of vascular malformation characterized by an abnormal aggregation of thin-walled blood vessels, which lack both elastic fiber layers and muscular layers (1). Histopathologically, these lesions are marked by vessel dilation, reduced contact between endothelial cells lining the vessels, and a deficiency in junctional complex proteins (1). Cavernous hemangiomas may occur sporadically or be inherited, with the latter associated with loss-of-function mutations in the KRIT1/CCM1, CCM2, or PDCD10/CCM3 genes (1, 6). The inheritance pattern is autosomal dominant, where a “second hit” mutation in the other functional allele precipitates disease onset (1) (Figure 5). Cerebral angiography typically does not reveal any large feeding arteries or draining veins. These hemangiomas are predominantly intracranial and infrequently occur within the spinal canal, with an annual incidence of 2.2 per 10 million, accounting for 5 to 12% of intraspinal vascular conditions (1). Based on their anatomical location, cavernous hemangiomas are classified into intramedullary, subdural extramedullary, epidural extramedullary, and vertebral body types (2, 5, 7, 8). Among these, the intramedullary type is the most prevalent, whereas the pure epidural type is relatively rare, representing only 4% of all neuraxial epidural tumors. Pagni et al. indicated that the onset of the disease typically occurred between the ages of 30 and 60 (9). The thoracic segment was the most frequently affected area, accounting for 54 to 60% of cases, whereas the cervical segment constituted 30%, and the lumbar segment comprised 10%. In our study, the cohort consisted of five female and two male patients, with a mean age of 49.4 years. Among these patients, five lesions were located in the thoracic spine, and one each in the cervical and lumbar spines, consistent with findings reported in the literature.

The clinical manifestations of this disease are non-specific and predominantly involve symptoms of spinal cord compression at the affected segment, such as numbness, weakness, and paraplegia in the limbs below the affected segment. The initial presentation of the disease varies in severity and is generally categorized into three forms (10–13): (1) A slow onset, characterized by initial radicular pain that gradually progresses to numbness in the limbs and sphincter dysfunction. All cases in our study exhibited this form, and due to the lack of distinctive clinical features, achieving a definitive diagnosis prior to surgery is challenging. (2) An intermittent onset, which may involve repeated minor bleeding or intratumoral thrombosis, leading to intermittent and recurrent symptoms. (3) Stroke onset, also referred to as acute spinal cord apoplexy was frequently caused by the rupture of malformed blood vessels due to exertion, strenuous activity, or childbirth. This resulted in a short-term hemorrhage and the formation of an intramedullary hematoma, leading to rapid disease progression and severe neurological impairment. The optimal timing for surgical intervention in such cases remained a topic of debate. Several researchers advocated for early surgical removal of the hematoma and malformed blood vessels to alleviate nerve compression symptoms and maximize the restoration of spinal cord function (4, 14–16). However, during the acute stage of hemorrhage, particularly in emergency surgeries, the distinction between normal tissues and hemangiomas was often unclear, which can lead to spinal cord injuries and adverse outcomes due to limited visibility. Therefore, it is advised to address dehydration initially and perform surgery after symptoms have been alleviated or stabilized to achieve optimal results. In our study cohort, all patients exhibited symptoms that developed gradually and were resolved following surgical treatment.

MRI is the primary modality for the imaging diagnosis of this disease; however, the literature indicated a high preoperative MRI misdiagnosis rate of 91.3% (2) (see Table 1). The authors retrospective analyzed patients from 2001 to 2018, the time was earlier than our series. Secondly, 3 T-MRI was applied regularly in our center. Moreover, we routinely conduct preoperative multidisciplinary discussions, which mainly consist of neurosurgeons, radiologists, and pathologists. These points were the reasons of our lower misdiagnosis rate. Three cases of our series were initially misdiagnosed as meningiomas prior to surgery (3/7, 42.9%), with one case not accurately identified during the operation, leading to an erroneous aspiration as surgical blood seepage. Inaccurate preoperative diagnoses could lead to various complications, such as misidentifying a tumor as blood seepage, resulting in its non-detection during surgery. The MRI characteristics of this disease include uniform isointense or hypointense signals on T1-weighted imaging (T1WI) and hyperintense signals on T2-weighted imaging (T2WI) (2, 5, 11, 12, 17). Occasionally, mixed T1WI and T2WI signals are observed due to factors such as rupture and hemorrhage of cavernous hemangiomas, hematoma organization following repeated bleeding, fibrosis, or peritumoral hemosiderin deposition, accompanied by homogeneous enhancement. The lesion typically affects multiple segments, presenting as a fusiform or oval mass aligned with the longitudinal axis of the spinal cord. It is well-demarcated from the surrounding tissue and exhibits a “double tail” sign on the sagittal T1 enhancement sequence. Within our group, the enhanced MRI demonstrated uniform enhancement, a well-defined border with adjacent areas, appearing like a fusiform mass aligned with the spinal cord’s longitudinal axis, along with typical “double tail” sign.

Differentiating the disease from neurogenic tumors, lymphomas, metastases, and meningiomas in the epidural space is essential. ① Neurogenic tumors are generally round and exhibit hypointense signals on T1-weighted imaging (T1WI), while appearing slightly hyperintense on T2-weighted imaging (T2WI). Some neurogenic tumors may undergo cystic degeneration and necrosis, resulting in heterogeneous signal intensity (17). Lymphomas typically present as isointense on T1WI and hyperintense on T2WI, with the potential for moderate to significant enhancement following contrast administration. This condition is often accompanied by other systemic manifestations, complicating differentiation from cavernous hemangiomas, which can be definitively identified through pathological examination post-surgery (11). Metastatic tumors are usually associated with swelling of adjacent soft tissues and bone destruction, characterized by hypointense signals on T1WI and hyperintense signals on T2WI. Metastases often display ring-like enhancements and rarely show the uniform enhancement characteristic of cavernous hemangiomas, typically originating from primary tumor sites (11). Meningiomas are primarily located in the extramedullary subdural space and generally exhibit isointense signals on both T1WI and T2WI (17). Upon enhancement, the lesion exhibits a distinct uniformity, albeit to a lesser extent than that observed in cavernous hemangiomas. Enhancement of the adjacent dura is frequently observed, often presenting a “meningeal tail sign,” whereas cavernous hemangiomas typically exhibit a “double tail sign.”

Histopathologically, the lesions are composed of mature vessels with thin walls lined by endothelium, interspersed with loose connective and adipose tissue (1). The vessel walls are primarily lined by a single layer of flattened endothelial cells within collagenous tissue, lacking elastic and muscular tissue or neuronal elements. Thrombosis and remnants of previous hemorrhages are also evident in cavernous hemangiomas, particularly in larger lesions.

Surgical excision is the preferred treatment modality for this condition. The fundamental surgical objective is to excise as much of the lesion as possible while minimizing the risk of spinal cord damage. This condition is characterized by the absence of large supplying arteries or draining veins and is predominantly located on the dorsal aspect of the epidural space. Consequently, complete resection of the hemangioma is recommended (1). Intraoperative neuroelectrophysiological monitoring, including motor evoked potentials (MEP) and somatosensory evoked potentials (SSEP), was routinely employed in our center. Typically, the PSECHs were mild with dural or nerve root adhesions and exhibited a relatively distinct interface, allowing for precise sharp anatomical separation during surgical procedures. These points were added in the discussion section. The application of low-power bipolar coagulation on the tumor surface can effectively reduce the size of the cavernous hemangioma, thereby facilitating its complete resection. Cavernous hemangiomas are often easily separable from the dura or spinal nerve roots; however, their separation becomes more challenging when they invade the intervertebral spaces. Postoperative radiotherapy serves as an effective adjunct for tumors that are not fully excised. Nonetheless, stereotactic radiotherapy may be considered, given that traditional radiotherapy is not widely employed due to the potential risk of spinal cord radiation damage (12). In this cohort, all patients underwent complete intraoperative excision without the need for postoperative radiotherapy.

Based on the assessment of patients’ recovery status before and after surgery, it is evident that the preoperative neurological function significantly influences postoperative recovery outcomes. Patients exhibiting favorable preoperative neurological function, primarily characterized by sensory symptoms, tend to experience positive postoperative recovery. Conversely, those with compromised preoperative neurological status, notably indicated by reduced muscle strength, demonstrate slower postoperative recovery. Hence, it is imperative to address cavernous hemangioma within the spinal canal promptly, as early surgical intervention prior to the onset of irreversible neurological damage can lead to optimal surgical outcomes.