Abstract
INTRODUCTION: Secondary bladder tumor is rare. We report a case of a bladder tumor initially thought to be a recurrence of non-muscle invasive bladder cancer that was ultimately identified as metastasis from gastric cancer treated 16 years prior. CASE PRESENTATION: A 75-year-old male with a history of gastric, prostate, and recurrent non-muscle invasive bladder cancer was diagnosed to have multiple bone metastases. Open bone biopsy and cancer gene panel testing identified the primary origin of the metastases as gastric cancer. Retrospective evaluation revealed that what was initially suspected as recurrent bladder tumors were actually metastases from the gastric cancer. CONCLUSION: In cases of metastases with an unknown primary origin, detailed evaluation, including biopsy of the metastatic lesion and genomic testing, is recommended.