Complex mucinous cystadenoma of undetermined malignant potential of the urachus

Abstract

Urachal mucinous neoplasms are rare and include both villousadenomas and invasive adenocarcinomas. These mucinous tumoursshould be completely excised as they can demonstrate aggressiveclinical behaviour, including the development of pseudomyxomaperitonei. We describe a 70-year-old woman who presented witha lower abdominal mass and received a diagnosis of a rare, complexurachal mucinous cystadenoma of undetermined malignant potential.This tumour demonstrated extensive mucin extravasation intoperivesical soft tissue, but was not associated with pseudomyxomaperitonei or any malignancy. Rarely described in the English literature,mucinous cystadenomas of the urachus should be treatedsimilarly to their villous adenoma counterparts: with complete surgicalexcision to prevent local tumour recurrences.