Assessment of indeterminate melanocytic choroidal tumours with optical coherence tomography: A cohort study

Abstract

Background: It is difficult to differentiate large choroidal naevi from small melanomas. The management of patients with such ‘indeterminate melanocytic tumours’ is controversial. This is because over-treatment of naevi can cause unnecessary visual loss whereas delayed treatment of melanoma may have fatal consequences. Several studies have shown that serous retinal detachment overlying an indeterminate melanocytic choroidal tumour predicts growth of these tumours; however, these studies have mostly been based on ophthalmoscopy. Optical coherence tomography (OCT) facilitates the detection of subtle retinal detachment. It is not known, however, whether minimal retinal detachment is clinically relevant. The aim of our study was to evaluate OCT as a tool for predicting growth of indeterminate melanocytic choroidal tumours. Methods: Forty-five patients with a recently-detected, indeterminate melanocytic choroidal tumour were examined with OCT and the findings were correlated with subsequent tumour growth. Results: After a mean follow-up of 15 months, 9 of 17 tumours with SRF showed growth as compared to 1 out of 28 tumours without SRF. Tumours with SRF increased in thickness by an average of +0.26mm [95% confidence interval (CI): -0.06 to +0.57] as compared to a mean decrease of -0.12mm [95% CI : -0.22 to -0.03] in tumours without SRF. Of the eight tumours requiring treatment because of observed growth, seven showed overlying SRF as compared to none of the tumours without SRF. Conclusions: OCT is useful in predicting growth of indeterminate melanocytic choroidal tumours.