Case Series: Different Presentations of Iris Melanoma-Potential Masquerade of Benign and Malignant

Yield of Multimodal Imaging in Iris Amelanotic Lesions: A Masked Case-Control Study

OBJECTIVES

To examine the yield of multimodal imaging of iris amelanotic lesions and evaluate the clinical relevance of these imaging techniques.

METHODS

In this masked case-control study, imaging, including slit lamp photos, ultrasound biomicroscopy (UBM), and anterior segment optical coherence tomography (AS-OCT) scans of patients diagnosed with iris amelanotic lesions were examined. Seven patients diagnosed with an iris amelanotic lesion were matched by gender and age to seven melanotic iris nevi of similar size and location. Two ocular imaging experts assessed the images in a masked manner and identified which lesion was melanotic and which was amelanotic based on their characteristics.

RESULTS

From 2010 to 2021, seven patients were diagnosed with amelanotic iris lesions. All were female; the mean (±SD) age at presentation was 46.3 years (±18). These patients were matched with seven female patients with pigmented iris lesions, with a mean (±SD) age of 49.8 years (±20). Hypopigmented lesions were hyporreflective and had minimal shadowing of the iris behind them, and the basement membrane of the iris could be seen on AS-OCT. Hypopigmented lesions could be delineated from the iris stroma on AS-OCT. In contrast, hyperpigmented lesions were hyperreflective, with significant shadowing blocking the basement membrane and iris stroma.

CONCLUSIONS

AS-OCT is non-touch and provides substantial information about diagnosing amelanotic nevi. It is more widely available and, in many countries, it is performed by technicians, thus freeing the physician's time and increasing productivity.

Cysts and tumours of the iris: Diagnostic tools and key management considerations-A review

The iris is a unique structure, with exquisite variations in colour and form. Pathological changes, specifically including iris cysts and tumours are relatively uncommon, difficult to diagnose, and yet potentially blinding or life-threatening. Based on a comprehensive literature review, with highly illustrated key case examples, this report aims to guide the clinician in filtering the differential diagnoses of iris cysts and tumours. Evaluation is in the context of key diagnostic clinical tools and management considerations. Diagnostic imaging techniques include serial anterior segment photography, ultrasound, anterior segment optical coherence tomography, and iris fluorescein angiography, however, the roles of computerised topography and magnetic resonance imaging are also considered in this review. Management includes categorisation in terms of solid iris tumours (melanocytic vs. non-melanocytic), or iris cysts (primary vs. secondary) that may be usefully differentiated by clinical assessment, avoiding more invasive interventions. Cystic lesions are generally benign, although implantation cysts in particular cause significant complications and surgical challenges. Most solid tumours are melanocytic and also typically benign. However, in larger lesions, rapid growth, symptoms and complications more likely indicate malignancy, requiring further investigation.