Orbital-adnexal lymphangiomas. A spectrum of hemodynamically isolated vascular hamartomas.

A retrospective review of 13 cases of lymphangioma has led to a classification of these lesions into categories of superficial, deep, and combined types. The clinical manifestations, prognosis, and management directly correlate with the pathophysiology and the location of the lesions. Superficial lesions consist of isolated multicystic vascular abnormalities of cosmetic significance only. Deep orbital lymphangiomas present as spontaneous, acute proptosis due to retrobulbar hemorrhage. Combined lesions demonstrate both superficial and deep components and are also characterized by spontaneous hemorrhages. Histopathologically, lymphangiomas represent a spectrum of vascular hamartomas with a constellation of features that parallels the clinical progression and histology of similar lesions elsewhere in the head and neck. This may include the presence of diaphanous serous-filled vascular channels, a connective tissue stroma with lymphorrhages, features of old hemorrhage, dysplastic vessels, and random smooth muscle bundles. Both direct and indirect evidence suggests that these lesions are characterized by relative hemodynamic isolation.