Figure 2. (a) 71-year-old man with lung cancer. FDG-PET demonstrating hypermetabolic foci in the left upper and left lower lung suggesting tumour recurrence (mediastinal adenopathy not shown). Hypermetabolic focus on the right side corresponds to posterior parts of the liver. In addition there is a hypermetabolic focus in the right buttock (arrows). (b) US of the right buttock. Poorly marginated, hyperechogenic lesion (1.9 cm diameter) surrounded by a less echogenic rim. (c) Histological image showing an accumulation of macrophages (arrows) within fibrous tissue. Immunostaining for anti-human macrophage CD 68 ( x 250).