The malignant mimic - Metastatic prostate carcinoma mimicking as papillary urothelial carcinoma

We report an interesting case of a 76-year-old male patient who presented with lower urinary tract symptoms and elevated prostate-specific antigen levels. Radiological investigations revealed transmural thickening of the posterior urinary bladder wall along with Grade 2 prostatomegaly. The patient underwent transurethral resection of the prostate (TURP) and transurethral resection of bladder tumor (TURBT) followed by histopathological evaluation of these samples. The TURP specimen on histopathology revealed features of prostatic acinar adenocarcinoma with a Gleason score of 4 + 5, whereas the TURBT showed features of papillary urothelial carcinoma on microscopy. However, on immunohistochemistry, the TURBT sample was positive for AMACR and negative for GATA3, which pointed toward its prostatic origin.