Significance of 99mTc-sulfur colloid splenic image in malignant melanoma

To evaluate the clinical significance of 99mTc-sulfur-colloid (TsSC) spleen scan findings in patients with malignant melanoma, a retrospective study was undertaken. Eighty-one patients with histologically proven malignant melanoma who received treatment in Roswell Park during a five-year period were included in this study. The scans were analyzed for spleen size, differential uptake of the tracer in liver and spleen, and for the presence of metastases in these two organs. These data were compared with stage of disease, survival, and autopsy findings. Significant correlation was found between the splenic size as measured on the scintiscan and at autopsy examination. The spleen size was found to be normal in 92% of the patients in early melanoma. The median survival of patients who had a normal-sized spleen by scan criteria was found to be longer than those who had splenomegaly. No significant difference in survival was noted between the patients with and without augmented splenic uptake of TcSC. Only a small number (17.7%) of patients with augmented splenic uptake had splenic metastases; hence, the possible role of immunological factors was considered.