Abstract: Objective  To investigate the clinical features and treatment of children orbital Langerhans cell histiocytosis (LCH). Design Retrospective case series. Participants  From April 2013 to May 2019, 7 patients (8 eyes) with orbital LCH were confirmed in the Second Affiliated Hospital of Air Force Military Medical University. Method The general  situation, clinical manifestations, imaging and general examination, pathological features, treatment plan and clinical follow-up results were summarized. Main Outcome Measures Clinical and pathological characteristics, treatment and follow-up results. Results Of the all 7 patients, 5 were unifocal lesions and 2 were multifocal lesions. All patients were male with an age range of 8 months to 10 years. Course range was 3 days to 2 months. The clinical manifestations of unifocal lesions were monocular, with eyelid swelling as the main symptom, 1 case with eyelid mass. The clinical manifestations of multifocal lesions were monocular or binocular eyes, with exophthalmos as the main symptom, and 1 case with red eyes and tears. On CT images in unifocal lesions, there were lateral and upper orbital soft tissue mass with typical wormlike destruction of peripheral cranio-orbital bone. In multifocal lesions, there was monocular or bilateral orbital soft tissue mass with multiple map bone defect of cranio-orbital bone, and 1 case with insect-like destruction of rib. There were iso-hypointense on T1-weighted MR imaging and iso-hyperintense mixed signals on T2-weighted imaging. With T1 enhancement, most of the cases lesions presented obvious marked enhancement at the edges and the surrounding tissues, and with heterogeneous obvious enhancement of the lesion center. On histopathology, there were clonal proliferation of pathological Langerhans cells with infiltration of monocytes, lymphocytes and eosinophils. On immunohistochemical staining, CD1a, CD207 and S100 were showed positive signals. In unifocal lesions, all the 5 cases were treated with complete resection, curettage of bone cavity and repair of bone defect, combined with intraoperative or postoperative local triamcinolone acetonide injection. In multifocal lesions, one patient with monocular involvement underwent complete resection, curettage of bone cavity and local triamcinolone acetonide injection, and the other patients with binocular involvement underwent surgical biopsy. Multifocal lesion patients were also treated with systemic intravenous chemotherapy after operation. In unifocal lesions, the lesions disappeared completely without recurrence and were followed up for 30-85 months. In multifocal lesions for the observation 12-13 months, the disease was stable during treatment. Conclusions Children orbital LCH has typical clinical manifestations of eyelid swelling or exophthalmos. CT or MRI imaging and pathological examination are the basis of diagnosis. Complete resection of the focus, curettage of the bone cavity and local corticosteroid injection should be selected for unifocal lesions. Patients with multifocal lesions should be examined to exclude other systemic diseases, and intravenous chemotherapy after surgical resection is needed. (Ophthalmol CHN, 2021, 30: 300-306)

Key words: orbital langerhans cell histiocytosis/clinical manifestations, orbital langerhans cell histiocytosis/treatment