Incidental Detection of a Radiation-Induced Soft-Tissue Sarcoma on 68Ga-PSMA PET/CT in a Patient Previously Treated for Prostate Cancer.

Radiation-induced sarcoma is a rare complication of radiation therapy. We describe the incidental detection of a radiation-induced undifferentiated soft-tissue sarcoma with increased uptake on Ga-68-labeled prostate-specific membrane antigen (PSMA) PET/CT in a prostate cancer patient previously treated with surgery and external-beam radiotherapy. Results were confirmed by histological analysis. Ga-68-PSMA is known to bind not only to PSMA-expressing prostate cancer cells but also to the neovasculature of various other solid tumors. A careful Ga-68-PSMA PET/CT review of previously irradiated areas is warranted so as not to miss radiation-induced sarcoma in prostate cancer patients.