Higher subfoveal choroidal thickness in choroidal melanomas than in choroidal nevi.

Purpose: To compare subfoveal choroidal thickness (SFCT) between eyes with choroidal melanoma and choroidal nevi.

Methods: Retrospective study of 126 consecutive patients in a tertiary ocular oncology center. Eyes with tumors located less than two disc-diameters from the fovea were excluded. In eyes with naevi, factors of potential transformation into melanoma were recorded (orange pigment, subretinal fluid, thickness >2 mm, diameter >5 mm, ultrasound hollowness). SFCT was assessed by 3 independent observers on horizontal spectral-domain OCT scans.

Results: Sixty-seven eyes with choroidal melanoma and 59 eyes with choroidal nevi were included. The melanoma and nevi groups did not differ in gender (P=0.14) nor age (P=0.34). There was a very good agreement between the three independent observers for SFCT measurements (intraclass correlation coefficient=0.89). Mean SFCT was higher in melanomas (294.3±89.9 µm) than naevi (260.3±76.7 µm) (P=0.013), and the difference remained significant between melanomas and 28 naevi with ≥2 growth risk factors (256.3±77.0 µm) (P=0.027). In a multivariate model, the significant contributors to SFCT were presence of melanoma (P=0.004), younger age (P<0.0001) and shorter lesion distance to the fovea (P=0.016).

Conclusion: SFCT may reflect the interplay between melanocytic tumors and their choroidal microenvironment. Its clinical utility should be explored in future studies.