The relationship between combined positron emission tomography/computed tomography and clinical and light microscopic findings in choroidal melanoma.

BACKGROUND

To investigate the correlation between the clinical and light microscopic features of choroidal melanoma with combined PET/CT findings.

METHODS

This is a retrospective interventional case series of 14 patients with choroidal melanoma referred to the vitreoretinal service at the Mayo Clinic, Rochester, MN. All underwent preoperative combined PET/CT scanning and enucleation. Standardized uptake values (SUV) were correlated with the clinical and light microscopic features of the choroidal melanomas.

RESULTS

All 14 eyes showed uptake. The mean patient age was 62 years (SD 12.5 years). The mean tumor thickness was 9.3 mm (range 3-23 mm). Histopathology showed choroidal melanoma in all with the following cell types: 6 mixed cell type, 7 spindle cell type, and 1 epithelioid cell type. The average of the SUV means was 3.7 (range 1.7-12.8). The individual SUV means were correlated with lesion thickness (r = 0.85; P < 0.01) and largest tumor basal diameter (r = 0.65; P = 0.01). Melanomas with focal necrosis (P = 0.03) and of the mixed cell type (P < 0.01) appeared to have higher SUV means.

CONCLUSIONS

The majority of the choroidal melanomas had low to medium mean SUVs. Lesion size accounted for a significant portion of the variation, though nonspecific necrosis and cell type were also associated with higher SUV means.