Echographic differential diagnosis of small choroidal solid lesions

Abstract

The differential diagnosis of small choroidal solid lesions is usually one of the most difficult problems for the echographist. In order to contribute to a rational solution of the problem the authors analyzed a series of 74 small (mean thickness ± S.D. = 2.7 ± 0.81 mm, min 1.8 mm, max 5 mm) choroidal ‘tumors’. The echographic features of the solid lesions were evaluated in terms of sensibility, specificity, positive predictive value (PPV) and negative predictive value (NPV). This series was composed of 10 melanomas, 18 metastatic carcinomas, 12 nevi, 8 hemangiomas, 7 clotted hemorrhages and 19 disciform macular degenerations. In particular the attention was focused on the differentiation of melanoma with respect to other lesions. The most effective echographic characteristics for individualizing the small choroidal melanomas were the spongy internal texture (sensibility 90%, specificity 48%, PPV 21%, NPV 97%) and the choroidal excavation (sensibility 70%, specificity 97%, PPV 78%, NPV 95%) in B-scan; in A-scan they were: medium internal reflectivity (sensibility 100%, specificity 47%, PPV 23%, NPV 100%), regular internal structure (sensibility 70%, specificity 80%, PPV 35%, NPV 94%) and spontaneous vascular movements (sensibility 20%, specificity 100%, PPV 100%, NPV 89%). According to these results and those obtained from the analysis of the other choroidal ‘tumors’, the authors suggest an echographic algorithm for the correct diagnosis of each type of solid lesion.