Biopsy-Proven Prostatic Metastasis From Diffuse-Type Gastric Adenocarcinoma Presenting With Bilateral Malignant Ureteric Obstruction: A Case Report.

Metastatic involvement of the prostate and bladder trigone from gastric adenocarcinoma is exceedingly rare. We report the case of a 38-year-old man with previously treated diffuse-type gastric adenocarcinoma who developed bilateral hydroureteronephrosis during surveillance. Cystoscopy demonstrated an Inflamed prostatic urethra with early papillary changes and abnormal trigonal mucosa with bilaterally narrowed ureteric orifices. Retrograde studies revealed bilateral mid-ureteric strictures without intraluminal lesions. Biopsies from the prostatic urethra and trigone confirmed metastatic gastric adenocarcinoma. Ureteric stents failed to provide adequate drainage, necessitating bilateral nephrostomy insertion. This case highlights an unusual pattern of lower genitourinary metastasis from diffuse gastric cancer and underscores the importance of histological confirmation and multidisciplinary management.