Non-invasive, low-grade papillary urothelial carcinoma in the urachus.

The urachus is a duct connecting the allantois with the fetal bladder, forming the median umbilical ligament; it usually obliterates during fetal life. Carcinomas arising from urachal remnants are rare but associated with a poor prognosis. We present one case of non-invasive urachal papillary urothelial carcinoma, and through a systematic literature search, we identified 12 additional cases of urachal urothelial carcinoma reported in English literature in the past 20 years. The cases were compared according to the Sheldon Staging System and the Mayo Staging System presented by Ashley et al in 2006, and both Staging Systems tend to predict clinical outcome. The urachal carcinoma is an important differential diagnosis in patients presenting with haematuria or an infraumbilical mass, because the symptoms may be sparse and diagnosis at an early stage is essential for successful treatment.