Abstract:AIM: To investigate the clinical features and prognosis of patients with orbital inflammatory myofibroblastic tumor (IMT). METHODS: This retrospective study collected clinical data from 22 patients diagnosed with orbital IMT based on histopathological examination. The patients were followed up to assess their prognosis. Clinical data from patients, including age, gender, course of disease, past medical history, primary symptoms, ophthalmologic examination findings, general condition, as well as imaging, laboratory, histopathological, and immunohistochemical results from digital records were collected. Orbital magnetic resonance imaging (MRI) and(or) computed tomography (CT) scans were performed to assess bone destruction of the mass, invasion of surrounding tissues, and any inflammatory changes in periorbital areas. RESULTS: The mean age of patients with orbital IMT was 28.24±3.30y, with a male-to-female ratio of 1.2:1. Main clinical manifestations were proptosis, blurred vision, palpable mass, and pain. Bone destruction and surrounding tissue invasion occurred in 72.73% and 54.55% of cases, respectively. Inflammatory changes in the periorbital site were observed in 77.27% of the patients. Hematoxylin and eosin staining showed proliferation of fibroblasts and myofibroblasts, accompanied by infiltration of lymphocytes and plasma cells. Immunohistochemical staining revealed that smooth muscle actin (SMA) and vimentin were positive in 100% of cases, while anaplastic lymphoma kinase (ALK) showed positivity in 47.37%. The recurrence rate of orbital IMT was 27.27%, and sarcomatous degeneration could occur. There were no significant correlations between recurrence and factors such as age, gender, laterality, duration of the disease, periorbital tissue invasion, bone destruction, periorbital inflammation, tumor size, fever, leukocytosis, or treatment (P>0.05). However, lymphadenopathy and a Ki-67 index of 10% or higher may be risk factors for recurrence (P=0.046; P=0.023). CONCLUSION: Orbital IMT is a locally invasive disease that may recur or lead to sarcomatoid degeneration, primarily affecting young and middle-aged patients. The presence of lymphadenopathy and a Ki-67 index of 10% or higher may signify a poor prognosis.