Low-grade myofibroblastic sarcoma of the orbit

Rationale: Low-grade myofibroblastic sarcoma (LGMS) is a malignant lesion composed of myofibroblasts. It is an uncommon tumor of unknown etiology that mainly develops in the bone or soft tissue and is most often reported in the head and neck, particularly in the tongue and oral cavity. Patient concerns: A 2-year-old girl, previously well and with no significant medical history or family history of other diseases, presented with a 2-week painless swelling of the right orbit. Diagnoses:Preoperative computed tomography (CT) revealed a large homogeneous enhancedmass, 21 13mm in size, located on lateral wall of the right orbit with bone absorption. The mass was resected and histopathological examination revealed LGMS of the orbit. Interventions: On May 2016, she underwent surgery without the additional postoperative treatment. Outcomes: The patient’s postoperative course was uneventful, and was discharged on the 6th day after surgery. During a year follow-up period, there was no recurrence of the postoperative CT. The patient and her family were satisfied with the result of the surgery. Lessons:Based on clinical characteristics and postoperative CT, we considered the mass may be a benign tumor. We completely resected along the capsule without an extensive surgical margin. However, postoperative histopathology diagnose LGMS, which shows a strong potential for local recurrence and vascular invasion. So we should close observation of the patient’s symptoms and sign. If the tumor has invaded adjacent tissues, we will use adjuvant chemotherapy or radiotherapy. Abbreviations: CT = computed tomography, IMT = inflammatory myofibroblastic tumor, LGMS = low-grade myofibroblastic sarcoma.