Iris cysts are rare among iris tumors. They are often localized in the pigmented epithelium and rarely in the iris stroma. Local complications are related to potential growth, which concerns mostly stromal cysts rather than pigment epithelium types.
High frequency ultrasonography contributes significantly to recognizing the structure and anatomic rapports of iris tumors by providing histological-like sections. This case illustrates the usefulness of this modern imaging technique in characterizing iris tumors and providing guidance to the management process.
An 18-month-old boy was referred to our department after an incidental discovery of an iris tumor by systemic control. Based on the Bébé-Vision test, the 10th line was followed. After the use of 0.5% atropine, objective refraction was +1.00 diopters in both eyes.
An ophthalmologic examination under general anesthesia revealed that the corneal diameter was 11 mm and the intraocular pressure was 15 mm Hg in both eyes. Before pupil dilation, the right eye showed no abnormality in the anterior segment (Figure 1A), but a pigmented mass appeared after mydriasis in the inferior quadrant (Figure 1B). The anterior segment was normal in the left eye. Fundus examination did not display any abnormality in both eyes.
The anterior segment. (A) Before dilatation, the anterior segment seems be normal and does not show any abnormal structure. (B) After dilation, the pigmented cyst becomes visible by overflowing the pupillary contour, but not obstructing the visual axis. Note the polylobed character.
High frequency ultrasonography using a 50-MHz probe showed an upper iris cyst divided into two parts (Figure 2A). The first part was in the back of the iris (Figure 2B) and the second part was rounded and protruding through a pupil edge into the anterior chamber (Figure 2C). The walls were thin, but no other abnormalities were noted and the iridocorneal angle was opened. No vascularization was detected using Doppler ultrasound (Figure 3).
High frequency ultrasonography. (A) Vertical section after dilatation showing an anechoic cyst with two parts, at the back of the iris and in the pupil, separated by a thin membrane (yellow arrow). Note an open iridocorneal angle (blue arrow). (B) Oblique section showing the polylobed character of the pupillary part of the cyst that is taken from the posterior surface of the iris (orange arrow). (C) Horizontal section showing the cyst has developed from the surrounding iris epithelium (white arrows).
Doppler ultrasound confirms the non-vascular nature of the iris cyst.
At this stage, the cyst that developed from the iris pigment epithelium was not complicated by visual axis obstruction or anterior chamber component compression.
Of all iris tumors, cysts accounted for 21% in a retrospective study.1 Furthermore, iris cysts are less frequent in children than in adults, with an incidence between 21% and 23%.2,3 These congenital cysts, which often develop between the two iris pigmented epithelium layers, can be classified into peripheral, middle, or pupillary cysts, depending on their location in the iris.2
In this case, by referring to the ultrasonography images, the cyst was classified as a mid-zonal cyst. After pupillary dilatation, its appearance could have been confused with ciliary melanoma, especially because it had a rounded shape and a pigmented mass.4
A mid-zonal cyst is generally not complicated, provided that its volume is not too large and does not occupy a large space in the anterior chamber.5 Alternatively, if there is a large number of peripheral cysts, the cysts may cause a direct closure of the iridocorneal angle. Additionally, the pupillary cyst may result in a visual axis obstruction, but rarely in a posterior synechiae.6,7
High frequency ultrasonography leads to a diagnosis by showing an anechoic cyst enclosed by hyperechoic walls, while simultaneously providing an appreciation of anterior segment reports. Currently, this test is necessary for each iridociliary tumor.8
In contrast to the stromal cyst, which has a tendency to grow and require treatment, the pigment epithelium cyst is usually stable, therefore needing no management.2 Roche et al.9 explained that stromal cysts tend to increase in volume, mainly because they absorb the aqueous humor by diffusion and cell phagocytosis. However, as a result of the existence of a watertight intercellular junction and the scarcity of phagosomes, pigmented epithelium cysts do not tend to show these characteristics.9
In some cases, the pigmented epithelium cyst may grow, thus requiring treatment. A cystotomy can be attempted with an Nd:YAG9 or argon10 laser, but recurrences are often seen.3 A fine needle aspiration of the cyst is practiced by some physicians and this is often combined with either an endolaser or, in some cases, microdiathermy to create a cystic wall symphysis.11,12 If this action fails, the cyst may reappear, thus requiring a stronger intervention such as an iridocyclectomy bloc excision.13
Even if it is a rare iris tumor, a cyst can be recognized by its clinical features. However, high frequency ultrasonography is often critical for diagnosis. The classification of a cyst is significant for monitoring its progress and for detecting specific complications associated with each location, ultimately leading to improved treatment and management processes.
- Shields CL, Kancherla S, Patel J, et al. Clinical survey of 3680 iris tumors based on patient age at presentation. Ophthalmology. 2012;119:407–414. doi:10.1016/j.ophtha.2011.07.059 [CrossRef]
- Shields JA, Shields CL, Lois N, Mercado G. Iris cysts in children: classification, incidence, and management. The 1998 Torrence A Makley Jr Lecture. Br J Ophthalmol. 1999;83:334–338. doi:10.1136/bjo.83.3.334 [CrossRef]
- Chaudhry S, Shoaib KK, Hing S, et al. Strategies for the management of congenital iris cysts. J Coll Physicians Surg Pak. 2016;26:S71–S73.
- Makley TA Jr, King GL. Multiple cysts of the iris and ciliary body simulating a malignant melanoma. Trans Am Acad Ophthalmol Otolaryngol. 1958;62:441–443.
- Donate D, Kodjikian L, Gambrelle J, Burillon C, Denis P. Buphthalmia secondary to congenital pigmented epithelial iris cyst [article in French]. J Fr Ophtalmol. 2004;27:496–500. doi:10.1016/S0181-5512(04)96170-0 [CrossRef]
- Obata R, Suzuki S, Numaga J, Araie M. Congenital iris bombé induced by large iris cysts. Arch Ophthalmol. 2003;121:906–907. doi:10.1001/archopht.121.6.906 [CrossRef]
- Tanihara H, Akita J, Honjo M, Honda Y. Angle closure caused by multiple, bilateral iridociliary cysts. Acta Ophthalmol Scand. 1997;75:216–217. doi:10.1111/j.1600-0420.1997.tb00128.x [CrossRef]
- Marigo FA, Esaki K, Finger PT, et al. Differential diagnosis of anterior segment cysts by ultrasound biomicroscopy. Ophthalmology. 1999;106:2131–2135. doi:10.1016/S0161-6420(99)90495-5 [CrossRef]
- Roche O, Orssaud C, Beby F, Dupont Monod S, Roquet W, Dufier JL. Ultrasound biomicroscopy and physiopathology of congenital iris cysts [article in French]. J Fr Ophtalmol. 2007;30:25–30. doi:10.1016/S0181-5512(07)89546-5 [CrossRef]
- Bron AJ, Wilson CB, Hill AR. Laser treatment of primary ring-shaped epithelial iris cyst. Br J Ophthalmol. 1984;68:859–865. doi:10.1136/bjo.68.12.859 [CrossRef]
- Haller JA, Stark WJ, Azab A, Thomsen RW, Gottsch JD. Surgical management of anterior chamber epithelial cysts. Am J Ophthalmol. 2003;135:309–313. doi:10.1016/S0002-9394(02)01960-8 [CrossRef]
- Shen CC, Netland PA, Wilson MW, Morris WR. Management of congenital nonpigmented iris cyst. Ophthalmology. 2006;113:1639. doi:10.1016/j.ophtha.2006.04.014 [CrossRef]
- Naumann GO, Rummelt V. Congenital non pigmented epithelial iris cyst removed by block-excision. Graefes Arch Clin Exp Ophthalmol. 1990;228:392–397. doi:10.1007/BF00927248 [CrossRef]