FIGURE 1. ^99mTc-IL2 scintigraphy (A) of a patient with a large melanoma (arrow) of the left gluteus (B). Despite the large size of the tumor, the distribution of radioactivity is inhomogeneous, reflecting patchy infiltration by activated T lymphocytes. T/B ratio was 1.81. (C) CD25 staining showed a mild positivity for neoplastic cells and a strong diffuse positivity for lymphocytes.