Giant urothelial carcinoma of unknown origin invading the sigmoid mesocolon – a case report

SummaryBackgroundTransitional cell carcinoma, also called urothelial carcinoma, is the most common malignancy of the urinary bladder. Additionally, it can develop in the lining of the renal pelvis, ureter, prostate and urethra. Exceptionally, cancer can arise from the urachus. Also primary transitional cell carcinoma of the endometrium or ovary is a rare entity.AimThe aim of this article was to present a case of giant urothelial carcinoma of unknown origin invading the sigmoid mesocolon.Case ReportWe report a rare case of urothelial carcinoma invading the sigmoid mesocolon in a 60-year-old female admitted to our department. The patient presented with a 25-cm intra-abdominal mass and 6-cm ulcerated lesion at the top of the umbilicus. Laparotomy was performed which demonstrated a huge polycystic and solid tumour of the sigmoid mesentery infiltrating the sigmoid colon and appendix. Appendectomy and resection of the tumour with an infi ltrated sigmoid loop were performed. A right ovarian cyst – not contiguous to the aforementioned tumour – was found at the time of the operation and excised. We also removed the 6-cm skin lesion in the umbilical area.Histopathological examination revealed urothelial carcinoma with squamous cell metaplasia of the sigmoid mesocolon with bowel and umbilical invasion.Concurrent desmoid cyst (mature teratoma) of the right ovary was found.ConclusionsIn conclusion, this patient with a sigmoid mesocolon invasion from urothelial carcinoma of unknown origin posed a diagnostic dilemma.