BACKGROUND Synovial sarcoma is a malignant mesenchymal neoplasm with variable epithelial differentiation. Most synovial sarcoma cases are reported in young adults and can arise in any body site. Notably, primary orbital synovial sarcoma is rare. CASE SUMMARY An 8-year-old east Asian girl with 1-month history of gradual painless proptosis and lacrimation of the right eye was admitted. The patient presented with painless proptosis, downward eyeball displacement, and upward movement disorders. According to clinical manifestations, imaging examinations and postoperative immunohistochemical examinations, the diagnosis was monophasic synovial sarcoma with calcification. The patient underwent anterior orbitotomy procedure for removal of the right orbital mass under general anesthesia. The diagnosis of monophasic synovial sarcoma with calcification was confirmed finally through histological and immunohistochemical exam. The follow-up period was 6 mo, and no recurrence was observed during this period. CONCLUSION Primary orbital monophasic synovial sarcoma with calcification is a rare sarcoma, and clinical manifestations and imaging results are not specific. The tumor may present similar features as a benign tumor. Comprehensive analysis of clinical, radiological, and pathological findings is critically important for making the right diagnosis. Conventional treatment approach for synovial sarcoma is surgical resection with adjuvant or neoadjuvant radiotherapy, which is highly effective for localized tumors.

BACKGROUND Solitary fibrous tumor (SFT) is predominant within the pleura but very rare in the orbit, which is why the diagnosis of orbital SFT poses challenges in clinical practice. Accordingly, an integrated approach that incorporates specific clinical features, histological, histopathological, and immunohistochemical (IHC) examinations, and molecular analyses is warranted. AIM To retrospectively explore the clinical and imaging characteristics, treatment, outcomes of a series of patients with orbital SFT. METHODS We conducted a retrospective review of a series of patients diagnosed with a histopathologic orbital SFT treated at a single institution. All data on demogra/phics, clinical characteristics, imaging, treatment, postoperative histopathological and IHC examinations, and prognosis were collected. RESULTS In total, 13 patients were enrolled, 7 (53.8%) of whom had the tumor located in the superomedial quadrant of the orbit. Computed tomography revealed a solitary ovoid lesion in 10 (76.9%) patients and irregular lesion in 3 (23.1%) patients. Magnetic resonance imaging results were as follows: On T1 weighted images, 3 (23.1%) patients had hypointense mixed signals, whereas 10 (76.9%) patients showed isointense mixed signals; on T2 weighted images (T2WI), 3 (23.1%), 4 (30.8%), and 6 (46.2%) patients exhibited hypointense mixed, isointense mixed, and hyperintense signals, respectively. Notably, 12 (92.3%) patients showed significant enhancement, whereas there were patchy slightly enhanced areas in the tumor. All patients were treated by surgery. IHC analysis demonstrated that the tumor cells were immunoreactive for CD34, CD99, STAT-6, and vimentin in all patients. The lesions showed Ki-67 positivity < 5% in 1 (7.7) patient, 5%-10% in 10 (76.9%), and > 10% in 2 (15.4%). Two (15.4%) patients exhibited tumor recurrence. CONCLUSION The clinical manifestations and radiologic characteristics of orbital SFT are diverse and not specific. Accurate diagnosis and treatment require detailed radiological and histopathological/IHC evaluation.