A radiation-related second primary gastrointestinal stromal tumor in the bladder

Abstract

Abstract A 69-year-old man underwent 78 Gy/39 Fr of intensity-modulated radiation therapy for prostate cancer. Seven years after radiotherapy, a nonpapillary bladder tumor was identified. Transurethral resection of the bladder tumor was performed, and the pathological diagnosis was spindle cell sarcoma. Immunostaining revealed KIT−, DOG1++, CD34−, Actin++, Cytokeratin−, Desmin−, S100 protein−, and Vimentin++. No tumor recurrence was observed until 17 months after tumor resection. DOG1 is strongly and specifically expressed in gastrointestinal stromal tumors. This was a rare case of bladder gastrointestinal stromal tumor as a radiation-related second primary tumor.