Understanding the clinical characteristics of SOM is of utmost importance in facilitating timely diagnosis and intervention. Our data revealed that SOM primarily impacted middle-aged women, with a majority of them experiencing ocular symptoms. Specifically, proptosis was observed in 99% of patients, eyelid edema in 63%, and decreased visual acuity in 43%. In contrast, only 20% of patients reported cranial symptoms like dizziness and headaches. These findings are consistent with previous research [2, 3–5, 7].
Radiological imaging, particularly CT and enhanced MRI, plays a pivotal role in diagnosing and treating SOM [1]. CT scans primarily identify bone alterations, whereas MRI scans determine the tumor’s extent. Our study revealed that all SOM patients (100%) exhibited hyperostosis on CT, with 88.9% displaying irregular hyperostosis edges. This CT imaging features may distinguish SOM from fibrous dysplasia, which is characterized by hyperostosis with smooth edges [8]. Prior research findings propose that the hyperostosis of SOM arises due to tumor cell infiltration into the bone interior [3, 9]. Consistently, our histopathology findings indicate that 91.4% of the analyzed bones exhibited the presence of meningioma cells, thereby emphasizing the urgent necessity for surgical excision of hypertrophic bone. Additionally, we have made a novel discovery that malignant SOM can occasionally manifest as osteolytic lesions spanning the entire layer, albeit infrequently (1 out of 27 cases). Our observation of the dural tail sign in all SOM patients is consistent with previous research [7]. In Song-tao Qi’s study on convexity meningiomas, it was suggested that tumor invasion could be associated with specific types of dural tail signs [10]. Consequently, a comprehensive removal of the dura may help minimize the risk of tumor recurrence. Although the superior orbital fissure serves as the primary communication channel between the two SOM parts, none of our patients exhibited its widening. Instead, some (15.4%) showed fissure narrowing, possibly due to the proliferation of enclosing bony structures, such as the sphenoid bone’s greater and lesser wings and body.
SOM is prone to recurrence, and the recurrence rate varies depending on the treatment method. The reported recurrence rate ranges from 21–50% [11–13]. In our study, the recurrence rate for patients who underwent Simpson grade I surgery in conjunction with postoperative radiotherapy was determined to be 13.9%, representing the most favorable outcome among all treatment modalities. Conversely, among patients who underwent incomplete resection (Simpson grade II and higher), a substantial majority of 100% (3 out of 3 individuals) experienced recurrence. Furthermore, the recurrence rate for patients who underwent incomplete resection combined with postoperative radiotherapy was equally significant, reaching 50% (2 out of 4 cases). This finding suggested that a comprehensive resection of SOM, along with postoperative radiotherapy, could effectively reduce the recurrence rates. Notably, SOM recurrence tends to occur slowly [14, 15]. In the present study, it was observed that the minimum duration for recurrence following the surgical procedure was 11.2 months, while the maximum duration recorded was 171.1 months.
The collaboration of ophthalmologists and neurosurgeons is imperative in order to attain maximal tumor resection and mitigate surgical complications. In our study, wherein both specialists jointly performed the surgeries, we observed an impressive Simpson grade I resection rate of 88% and a relatively low postoperative complication rate of 27.5%. We recommend combined pterygopoint and orbital wall dissection approach, supplemented by a frontotemporal method. This integrated methodology provides enhanced tumor visibility, allowing for multi-angle observation, broader resection, and improved decompression of orbital content. Moreover, it significantly mitigates stress on the temporal lobe. By resecting the anterior bed process and opening the optic canal, the length of the optic nerve within the internal carotid triangle is effectively doubled, expanding its area of exposure. This facilitates decompression of the optic canal, which has been suggested by previous studies to potentially improve postoperative patient outcomes [12, 16]. When the tumors are fully exposed, it is advised that the ophthalmologist initially excise the intraorbital tumor, followed by the sequential removal of epidural and intradural tumors by the neurosurgeon. This procedural approach not only enhances the anterior surgical field, ensuring an unobstructed visual field, but also enables a thorough examination of the tumor from various perspectives and facilitates appropriate directional separation. To achieve complete eradication of SOM lesions and minimize the likelihood of recurrence, it is imperative to excise not only the primary tumor, but also the degenerated bone and affected meninges.
Postoperative pathological results showed that the predominant histopathological subtype of SOM is endothelial, corroborating earlier studies [17, 18]. Uniquely, we conducted a comparative analysis between the intracranial and intraorbital segments of the SOM tumors, revealing that the intracranial component exhibited a lower fibrous composition and a higher degree of vascularization in contrast to its orbital counterpart. This observation suggested that the intracranial tumor segment possessed a softer consistency, heightened vulnerability to compression, and an increased propensity for bleeding when compared to the orbital section. As a result, surgeons are advised to exercise caution during the management of intracranial tumors in SOM cases, emphasizing delicate manipulation techniques and minimizing direct clamping of tumor tissue.
This study is subject to inherent limitations characteristic of retrospective research, such as potential selection bias and reliance on the accuracy and completeness of medical records. It is worth noting that only 61 patients in this group had access to comprehensive long-term medical records, which is a common occurrence in retrospective reviews and highlights the possibility of missing or incomplete data. Furthermore, it is important to acknowledge that the data collection was exclusively conducted at a single medical center, which might constrain the generalizability of our findings to broader populations or regions. Nevertheless, it is noteworthy that our patient cohort is diverse, encompassing individuals from various regions across China, partially mitigating this limitation. Additionally, this single-center approach ensures standardized surgical procedures, enhancing the consistency of our treatment data.
Taken together, SOM predominantly affects middle-aged women and the primary clinical presentation is proptosis. On CT scans, SOM often presents as hyperostosis of the sphenoid wing, characterized by roughened surfaces. Enhanced MRI delineates the tumor’s extent, displaying iso- to hypointense signals on T1-weighted images and hyper- to isointense signals on T2-weighted images. Gross total resection combined with adjuvant radiotherapy could minimize recurrence rate. Meningothelial tumors are the most prevalent histological subtype. Notably, the intracranial component of SOM tumor, being less fibrous and more vascular, tends to be softer and more fragile, making it bleed-prone.