Optical Coherence Tomography in Benign and Malignant Melanocytic Tumors

Overview

Purpose:
To investigate the input of optical coherence tomography (OCT) in evaluation of tissue changes in small choroidal melanocytic lesions.

Methods:
We reviewed charts of 20 patients with uveal melanocytic tumors (9 with benign lesions and 11 with malignant ones). The best-corrected visual acuity (BCVA) was of 1.0–0.1 in the benign lesions and of 1.0–0.07 in the malignant ones at the time of presentation. Both fundi were examined after pupil dilatation using an indirect ophthalmoscope and a Goldmann lens. The tumor and the macula were captured and the ultrasound (US) was performed in all patients. Height of the tumor was of 1.3–1.7 mm in the benign lesions and of 1.40–2.8 mm in the malignant ones at presentation. The OCT scans have been placed to document the apex, the slope and the base of the tumor and the macula. The retinal thickness at the fixation point (RTFP) and the macular volume were of 140–357 μm and 6.1–7.6 mm3 respectively in benign lesions, and of 173–680 μm and 5.9–14.4 mm³ respectively in malignant ones at the presentation. Fluorescein angiography was indicated in 9 patients and indocyanine green in 8 of them. The follow-up period varied between 6 and 24 months in benign lesions and from 6 to 48 months in malignant ones. The following methods were used when indicated: laser photocoagulation, photodynamic therapy with verteporfin, brachytherapy, Leksell Gamma Knife irradiation, enucleation or combination of them.

Results:
The BCVA remained the same in the benign lesions but worsened to 0.8–0 in the malignant ones; the height of the tumor on US did not change in benign lesions and measured of 1.4–2.8 mm in malignant ones; RTFP and macular volume on OCT were of 156 – 412 μm and 7.1–8.2 mm3 respectively in benign lesions and of 124–506 μm and 3.8–8.8 mm³ respectively in malignant ones at the last visit. Qualitative analysis included the presence of subretinal and intraretinal fluid, convex deformity of the scan, increased reflectivity of the retinal pigment epithelium (RPE) or the choroid and disruption of the RPE.

Conclusion:
It seems that OCT is one of the most important examination methods to distinguish small choroidal melanocytic lesions to be benign or malignant. OCT findings play important role to detect the active lesion that requires treatment before it starts to grow. It is needed to enlarge our study group and to increase its follow-up period.

Key words:
optical coherence tomography, choroidal melanocytic tumor, retinal thickness, macular volume