Is growth of choroidal nevi associated with malignant transformation?

Researchers assessed whether widely used clinical risk factors for growth of choroidal nevi were associated with malignant transformation.

Study design

This multicenter, retrospective study included patients who underwent fine needle biopsy for lesions diagnosed as suspicious choroidal nevus or small choroidal melanoma with tumor thickness of 3.5 mm or less. Lesions were mostly confined to choroid (90%). The authors decided to biopsy based on documented growth or the presence of multiple clinical risk factors for growth. The main purpose was to test the used clinical factors for growth in small choroidal melanocytic lesions (choroidal nevi), using class 2 gene expression profile as a valid marker.

Outcomes

Documented growth was not associated with the class 2 profile (P= 0.5). The odds ratio of a tumor having the class 2 profile was higher for patients older than 60 years (OR 2.8) and for tumor thickness greater than 2.25 mm (OR 3.5). No other clinical feature or combination of features associated with the class 2 profile.

Limitations

The authors did not include newer diagnostic modalities that could potentially increase the ability to noninvasively distinguish class 2 tumors. There was lack of uniform criteria for biopsy and a potential bias in patient selection, both of which are common shortcomings of retrospective studies. 

Clinical significance

None of the widely used choroidal nevus risk factors for tumor growth, nor documented growth itself, are indicative of malignant transformation as defined by class 2 gene expression profile. Patient age and tumor thickness may be helpful for identifying small choroidal melanocytic tumors that are more likely to have the class 2 profile. Observation for growth prior to treatment continues to be reasonable for most patients with suspicious choroidal nevi.