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[Optical coherence tomography in diagnostics of small choroidal melanoma].

PURPOSE
To determine signs of small choroidal melanoma with different pigmentation using enhanced depth imaging optical coherence tomography (EDI-OCT).


MATERIAL AND METHODS
The study included 344 patients with small choroidal melanoma with different pigmentation examined using EDI-OCT: 1st group - pigmented melanoma (228 eyes), 2nd group - low pigmented (65 eyes), and 3rd group - amelanotic (51 eyes).


RESULTS
In pigmented small choroidal melanomas - elevation of choroidal profile towards vitreous, compression of choriocapillaries with a narrow even 'belt' and a 'shadow' effect; thinning, defects in Bruch's membrane; thickening of the retina above the tumor, lobulated photoreceptors; intra- and subretinal exudate (diffuse, cystic edema, neuroepithelial detachment); defects and detachment of pigment epithelium with hyperreflective foci, disorganization of the pigment with the formation of hyperreflective foci at different retinal levels. In low-pigmented small choroidal melanomas - elevation of choroidal profile towards vitreous, visualized inner surface of the sclera, 'excavation' of the choroid, enlarged choriocapillaries, contour of tumor; thickening of the retina, accumulation of intra- and subretinal exudate (local neuroepithelial detachments); disorganization of the pigment in pigment epithelium with hyperreflective foci in the outer retinal layers. In amelanotic small choroidal melanomas - elevation of choroidal profile towards vitreous, visualized inner surface of the sclera, 'excavation' of the choroid; contouring of choriocapillaries, longitudinal hyperreflective bands in the tumoral stroma, smoothness of the Bruch`s membrane, structural losses of photoreceptors; thickening of the retina (neuroepithelial detachment, diffuse edema); uneven thickening of pigment epithelium.


CONCLUSION
EDI-OCT can help identify microstructural changes in the choroid and adjacent retina in small choroidal melanomas with different degrees of pigmentation, suggesting at the early stages a more aggressive course of the tumoral process affecting the prognosis of the disease. In addition, identification of the microstructure and degree of pigmentation of initial choroidal melanomas is necessary for planning an organ-preserving treatment.