FDG PET of alveolar soft part sarcoma.

Alveolar soft part sarcoma (ASPS) is a very rare, but distinctive type of soft tissue sarcoma, whose name is derived from the pseudoalveolar appearance of its histology. In this report, the FDG PET/CT findings of ASPS are described in a 17-year-old asthmatic female who presented with worsening respiratory symptoms and a pelvic mass. The staging PET showed heterogeneous intense incorporation of FDG within the mass and variable FDG incorporation within the multiple lung nodules. In concordance with other soft tissue sarcomas, PET/CT helped to confirm the anatomic origin of the ASPS, to direct its biopsy, and to assess the distribution of disease.