Complex mucinous cystadenoma of undetermined malignant potential of the urachus: a rare case with review of the literature.

Urachal carcinoma is an uncommon neoplasm. Benign urachal tumours are extremely rare. All urachal mucinous tumours, regardless of tumour type, have the potential to behave in an aggressive clinical manner that includes the development of pseudomyxoma peritonei.