A 62-year-old man undergoes TURBT for a tumour at the dome of the bladder. Histology shows a mucin-producing adenocarcinoma with signet ring cells, arising in an area with no adjacent urothelial carcinoma in situ. Which origin best explains this tumour?

• A Metastasis from gastric carcinoma
• B Urachal remnant ✓
• C Direct invasion from sigmoid colon cancer
• D Squamous metaplasia of the trigone

Explanation

Mucinous or signet ring adenocarcinoma at the bladder dome or anterior wall, without urothelial carcinoma in situ elsewhere, is characteristic of urachal carcinoma arising from the embryological urachal remnant along the median umbilical ligament. Treatment is partial cystectomy with en bloc excision of the urachus and umbilicus. Dome location excludes trigonal squamous pathology, and absence of a known primary plus the typical site makes gastric and colonic metastasis far less likely.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.