Retained intraocular foreign body masquerading as malignant melanoma of the iris

Abstract

Dear Editor, Several non-neoplastic lesions of the iris, such as anterior staphyloma, iris stromal atrophy, iris nevus, iris cysts, Cogan-Reese syndrome, peripheral anterior synechia, inflammatory iris mass and prostaglandin-induced iris pigmentation can clinically look like a malignant melanoma of the iris [1–3]. Failure to recognize such a process could lead to excessive or superfluous therapy. We would like to present a 45-year-old male who visited our department with complaints of photophobia, hyperemia of the right eye and a small peripheral located melanocytic iris lesion. Findings from slit-lamp and dilated fundoscopic examination of the right eye were unremarkable, apart from a slightly mild inflamed anterior chamber and a 0.9×2.0mm elevated and heavily pigmented lesion, which was in close proximity with the chamber angle (Fig. 1). Gonioscopic examination revealed a pigmented mass in the angle with no spread to the iris. On stringent questioning, our patient recalled being hit in the right eye 30 years earlier with a heavy metal fragment. Archived files confirmed a deep-seated corneal erosion in 1976 and, at that time, a foreign body could not be found. On re-examination, the tumor pattern presented more as a sharp linear lesion than as a foreign body. There was no evidence for ocular siderosis. Echo-B 50 MHz ultrasound examination revealed a high-reflective lesion in the chamber angle without extension, highly indicative of a metallic foreign body. In day care, the foreign body was removed microscopically via corneal route from the anterior segment (Fig. 2). This case emphasizes the importance of careful history taking, gonioscopic examination and imaging modalities. When ocular history and slit-lamp examination does not reveal any evidence for ocular trauma, the diagnosis of foreign body may be difficult. Techniques such as orbital X–ray, ultrasound biomicroscopy and computed tomography looking for atypical features are essential in such situations [4, 5]. When confronted with a dark iris lesion with characteristics which are not in accordance with features normally seen in iris melanoma diagnosis, a foreign body should be considered in the differential diagnosis, even if the incident may have occurred years ago. Shields et al. reported that iris foreign bodies accounted up to 4.5% of pseudomelanomas in a clinical Graefes Arch Clin Exp Ophthalmol (2008) 246:623–624 DOI 10.1007/s00417-007-0702-6