2020–2021 BCSC Basic and Clinical Science Course™
4 Ophthalmic Pathology and Intraocular Tumors
Part I: Ophthalmic Pathology
Chapter 14: Orbit and Lacrimal Drainage System
Orbital lymphatic malformations (previously termed lymphangiomas) typically present in childhood and are characterized by recurrent and fluctuating proptosis, often enlarging in the setting of upper respiratory tract infection. They are unencapsulated, diffusely infiltrating proliferations of vascular channels with lymphatic differentiation and scattered lymphoid aggregates with a fibrotic interstitium (Fig 14-11).
Figure 14-10 Low-grade B-cell lymphoma of the orbit. A, Low-magnification photomicrograph shows sheets of small, dense, uniform lymphocytes forming vague follicular arrangements (arrows).B, Higher magnification shows a lymphoid follicle with a germinal center (asterisk).C, Dutcher bodies, typical for marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT), are seen within the nuclei (arrows).
(Courtesy of Heather Potter, MD.)
Orbital hemangiomas in adults are typically located intraconally and are encapsulated, consisting of large, irregular cavernous spaces (cavernous hemangioma) with relatively thin, fibromuscular walls (Fig 14-12). Vessels may show thrombosis and calcification. Cavernous hemangiomas are considered to be circumscribed, low-flow venous malformations. In contrast, hemangiomas in children are unencapsulated and more cellular, often with a cutaneous component, and are composed of capillary-sized vessels (infantile [capillary] hemangioma). See Chapter 13 for more information on infantile hemangioma.
Nassiri N, Rootman J, Rootman DB, Goldberg RA. Orbital lymphaticovenous malformations: current and future treatments. Surv Ophthalmol. 2015;60(5):383–405.
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.