[Optical coherence tomography angiography in the differential diagnosis of iris melanoma and progressive iris nevus]

Considering the similarity in clinical presentations of iris neoplasms of various origins, questions of their noninvasive diagnosis remain relevant. Optical coherence tomography angiography (OCT-A) is one of the imaging method that enables visualization of tumor vessels.

This article examines the features of angioarchitecture, vascular network density, and perfusion density of iris melanoma and progressive iris nevus using OCT-A.

A total of 67 patients with iris neoplasms were examined between 2021 and 2023. Group 1 included 29 patients with progressive nevus, while group 2 included 38 patients with iris melanoma, which was further divided into two subgroups (A - 32 patients with planar growth, B - six patients with nodular growth). All patients underwent OCT-A with analysis of qualitative and quantitative characteristics. Diagnoses were morphologically verified in all cases.

In one-third of cases, OCT-A of pigmented melanomas and progressive iris nevi revealed single hyperreflective vessels, while signal blocking was noted in other cases. In hypopigmented forms of progressive nevus, single hyperreflective vessels were observed, with a mean vascular network density of 5.1±2.9 mm^-¹ and perfusion density of 11.7±3.2%. Hypopigmented forms of iris melanoma showed multiple, chaotically arranged hyperreflective vessels, with a mean density of 11.1±2.6 mm^-¹ (p<0.05) and perfusion density of 34.3±7.6% (p=0.01), significantly exceeding these values in progressive nevi.

OCT-A enables detection of tumor vessels primarily in hypopigmented forms of iris melanoma and progressive nevus. Increased vascular network density and perfusion, along with the presence of multiple chaotically arranged hyperreflective vessels, allows for differential diagnosis between melanoma and progressive iris nevus and facilitates appropriate organ-preserving treatment.