Lipomas are rare in the orbit. Their pathologic characteristics include encapsulation and a distinctive lobular appearance. Because lipomas are difficult to distinguish from normal or prolapsed fat histologically, their incidence may have been overestimated previously.
Like lipomas, liposarcomas are rare in the orbit. Liposarcomas are malignant tumors with adipose differentiation. They are categorized as several histologic variants. Histologic criteria for diagnosis depend on the type of liposarcoma, but the unifying diagnostic feature is the presence of lipoblasts. Cytogenetic and/or molecular studies for chromosome translocations and alterations in several genes, including MDM2, can be very useful for diagnosing and grading adipose tumors. Liposarcomas tend to recur before they metastasize.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.