The histopathological analysis of transurethral resection of bladder tumor specimen revealed a tumor cell arranged in a sinusoidal pattern and immunohistochemistry analysis showed the tumor cell was positive for Thyroid transcription factor-1 (TTF-1), paired box gene 8 (PAX-8), and thyroglobulin establishing a diagnosis for metastatic urinary bladder lesion of thyroid origin. This evidence concerns the gene PAX8 and neoplasm.