Background: There has been controversy over whether orbital lymphangioma is a true entity in the orbit or various venous malformations.
Case: A 1-year-old girl was referred to us with subcutaneous induration of the right upper eyelid. Rapid enlargement of the eyelid mass with blepharoptosis and dislocation of the eyeball were noted within 1 week. A diagnosis of an orbital lymphangioma was made from the clinical course and findings of magnetic resonance imaging. Surgical resection of the tumor was performed to prevent amblyopia.
Observations: Histopathologically, the lumen of the expanded cystic tumor consisted of a single layer of endothelium and was filled with erythrocytes as well as lymph. Immunohistochemical study revealed positive staining for factor VIII-related protein and CD 31, weak positive staining for thrombomodulin, and negative staining for CD 34 at the endothelium of the lymphangioma. The endothelium of the capillary vessels around the lymphangioma was positive for factor VIII-related protein, CD 31, and CD 34. Although a part of the tumor remained in the orbit postoperatively, orthophoria was achieved and no recurrence was observed for 2 years.
Conclusion: Immunohistochemical study suggested that the cellular composition of the endothelium of the orbital lymphangioma was different from that of the surrounding capillary vessels.