Compressive Retinal Degeneration Due to a Large Lacrimal Gland Tumor
A 64-year-old man presented with painless, progressive proptosis of the OS that lasted for several years. Clinical examination revealed severe downward deviation of the eyeball and a firm palpable mass above the eyeball (Fig. 1A). Visual acuity was “hand motion,” and the fundus could not be observed because of hypermature cataract. B-scan ultrasound revealed severe compression of the upper eyeball by the orbital mass (Fig. 1B), and MRI revealed a 3.5 cm-sized well-defined round mass above the eyeball (Fig. 1C,D).
Complete excisional biopsy of the mass was performed and diagnosed as pleomorphic adenoma of the lacrimal gland (Fig. 1E). Cataract surgery was performed after 2 months, and a degenerative retinal change was observed in the superior retina at the site of previous tumor compression (Fig. 2A). The optic disc showed no sign of optic atrophy (Fig. 2B). Optical coherence tomography (OCT) revealed dense sub-retinal pigment epithelium (RPE) material (red asterisk) and choroidal thinning (arrow heads) which were more prominent on the affected superior side (red dashed arrow) than inferior area (green dashed arrow, Fig. 2C). Choroidal thickness in the opposite eye was normal (Fig. 2D).
The possibility of retinal degeneration by other etiologies cannot be completely ruled out. However, given the fact that degenerative retinal changes have been observed at previous tumor compression sites, the possibility of retinal degeneration by long-term compression can also be assumed. The possible pathophysiology is that the large orbital tumor mainly compresses the posterior ciliary arteries and affects choroidal circulation, while relatively conserving the central retinal artery traversing inside the optic nerve. Choroidal blood flow compromised over a long period can cause choroidal thinning and induce outer retinal and RPE degeneration. The diffuse sub-RPE deposits could be due to the outer retinal metabolite clearance failure caused by RPE dysfunction.© 2020 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.