Unilateral acute iris transillumination syndrome with glaucoma and iris pigment epithelium dispersion simulating iris melanoma

Abstract

Purpose: To report a patient with a unilateral presentation of glaucoma, pain, and acute iris transillumination syndrome simulating iris melanoma.

Observations: A 53-year-old male presented with blurred vision and pain in his right eye several weeks following a respiratory sinus infection managed by oral azithromycin. Examination of the right eye was notable for elevated intraocular pressure of 46 mm Hg, an irregular mid-dilated pupil, and diffuse iris transillumination with pigmentary seeding on the iris surface, in the anterior chamber angle, and on the sclera, suspicious for diffuse iris melanoma with glaucoma and extrascleral extension. Ultrasound biomicroscopy (UBM) of the right eye revealed circumferential anterior chamber angle and trabecular meshwork involvement by an infiltrative process corresponding to the pigmented cells noted clinically, while the ciliary body was unremarkable. Following enucleation, histopathology showed extensive necrosis of the iris pigment epithelium, sphincter, and dilator muscles with melanophagic infiltration in the anterior chamber angle and episclera, mild chronic non-granulomatous iridocyclitis, and no evidence of a melanocytic neoplasm. Although immunohistochemical studies for herpes simplex virus (HSV) types 1 and 2, varicella-zoster virus, and cytomegalovirus were negative, qualitative real-time polymerase chain reaction on paraffin-embedded tissue detected HSV-1 DNA. The combined clinical, pathologic, and molecular findings were compatible with unilateral acute iris transillumination syndrome, likely HSV-1 associated.

Conclusion and importance: Unilateral acute iris transillumination syndrome with diffuse iris pigment epithelial loss can simulate iris melanoma. Prompt herpes viral studies may be informative.

Keywords: Azithromycin; BADI; BAIT; Bilateral acute iris depigmentation; Bilateral acute iris transillumination; Glaucoma; HSV; Herpes simplex virus; Iris melanoma; Pigment dispersion; UAIT; Unilateral acute iris transillumination.

Fig. 1

Unilateral acute iris transillumination, clinical findings. A, The right eye showing a mydriatic, irregular pupil and multiple foci of episcleral pigment (arrowheads) adjacent to mildly dilated vessels. There is no appreciable iris stromal atrophy. B, Normal anterior segment of the left eye. C, Retroillumination of the right eye showing diffuse iris transillumination. D, Retroillumination of the left eye was normal. E, Gonioscopy of the right eye showing intense diffuse pigmentation of the angle with pigment dusting along the iris stroma (arrow). F, Gonioscopy of the left eye angle is without pigment deposition.

Fig. 2

Unilateral acute iris transillumination, imaging findings. A, Enhanced depth imaging anterior segment optical coherence tomography (AS-OCT) of the right eye showing a lack of posterior bowing of the iris surface. B, Higher magnification shows clumping of the iris pigment epithelium along the pupillary margin (arrowhead), focal disruption and absence of the iris pigment epithelium (arrow) and thickening of the adjacent iris root. C, Anterior segment ultrasound biomicroscopy (UBM) showing thickening of the inferior anterior chamber angle structures (arrowhead) and hyper-reflective foci (arrow) suggestive of pigmented cell dispersion adjacent to the unremarkable ciliary body. D, UBM of the inferior anterior chamber angle shows thickening of the iris root and effacement of the anterior chamber angle structures (arrowhead).

Fig. 3

Unilateral acute iris transillumination, macroscopic findings. A, Diffuse intense pigment in the anterior chamber angle (red arrow). B, Higher magnification highlights anterior chamber angle pigment (red arrow) and dusting of pigment on the surface of the iris (red arrowhead). C, Sectioned trabecular meshwork is filled with pigment (single red arrow). Pigment is seen on lens zonular fibers (white arrhoweads). Iris pigment epithelium is markedly disrupted and focally absent (two red arrows). D, Higher magnification shows focal absence of iris pigment epithelium (white arrowheads) and pigment deposits in the iris stroma (red arrow), on the anterior surface of the iris (white arrows), within the trabecular meshwork (black arrowhead), and intrascleral emissarial canals (red arrowhead). E, Scattered pigmented cells on the surface of the iris. F, The underside of the iris shows patchy areas of depigmentation with loss of iris pigment epithelium (arrows). The underlying ciliary processes of pars plicata (arrowheads) are unremarkable. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 4

Unilateral acute iris transillumination, histopathologic findings. A, Markedly disrupted and focally absent iris pigment epithelium (arrowheads), pigment in the anterior chamber angle (single thick arrow), and on epibulbar surface (two thin arrows). B, Higher magnification highlights absent and clumped iris pigment epithelium (black arrowheads), and melanophages within the trabecular meshwork (arrow). There is a sparse lymphocytic infiltrate in the iris root (red arrowhead), magnified in an inset. C, Higher magnification of the anterior chamber angle shows melanophagic infiltrate in the trabecular meshwork (black arrow), on the surface of the iris root (arrowhead), and in the iris stroma (two red arrows). Disrupted iris pigment epithelium at the bottom of the image. D, Pupillary portion of the iris showing extensive necrosis of the iris sphincter (red asterisk), associated with an infiltrate of intensely pigmented melanophages, focal vascular occlusion (red arrow), and stromal paucicellularity (black asterisk). Iris pigment epithelium is essentially absent (black arrows). E, Body of the iris showing disruption and loss of iris pigment epithelium (black arrow) with a melanophagic infiltrate in the overlying stroma (red arrow). There is absence (necrosis) of the dilator muscle. F, Cluster of darkly pigmented melanophages (arrow) and small dark blue lymphocytes surround episcleral vessels, which are focally dilated (arrowhead). [hematoxylin-eosin; 100x (A), 200x (B), 400x (C, E, F), 630x (D, B-inset)]. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)