[Values and limitations of radioimmunoscintigraphy with MoAb 225-28S in the diagnosis of posterior uveal melanoma].

When evaluating a clinical situation in which a posterior uveal melanoma (PUM) is suspected, we have to use all available diagnostic procedures because it may be difficult to distinguish between amelanotic tumours and/or small melanomas. Early diagnosis of a small lesion is mandatory for successful conservative therapy. Radioimmunoscintigraphy (RIS) of malignant melanoma has become an encouraging tool in Nuclear Medicine. 99mTc labelled F (ab')2 fragments of MoAb 225-28S raised against cutaneous melanoma were used. Nine patients were examined: the clinical diagnosis was PUM in 7 cases and choroidal metastases in 2 cases. Due to the size and/or site of the tumor, six eyes were enucleated. In all of these cases histopathology revealed a malignant melanoma. One patient died with disseminated hepatic metastases, 2 months after observation. RIS was positive in 5 of 7 PUM (71.4%) and a false negative result was obtained in 2 patients. Two true negative scintigraphies were observed in the patients with breast carcinomas and choroidal metastases. On the basis of these results, RIS may be valuable to diagnose ocular malignant melanoma, but specificity of MoAb 225-28S needs to be assessed.