Urachal Mucinous Cystic Tumour of Low Malignant Potential With Incidental Clinical Presentation: A Case Report With Clinicopathologic Features and Review of the Literature

Urachal mucinous cystic tumour of low malignant potential (MCTLMP) is a rare cystic epithelial neoplasm of urachal origin, with fewer than 50 cases described as such in the English‐language scientific literature. This case report describes an instance of urachal MCTLMP discovered incidentally in a 59‐year‐old female patient following the performance of imaging studies for an unrelated condition: Management consisted of surgical resection of the tumour and partial cystectomy, with no complications and no recurrence after 10 months of follow‐up. Sections of the partial cystectomy specimen demonstrated histological features that were reminiscent of a low‐grade appendiceal neoplasm or a borderline ovarian mucinous neoplasm, which were favoured to represent urachal MCTLMP. This case report highlights the clinical importance of both the complete surgical resection of tumour and the exclusion of secondary involvement of the bladder or urachus by a glandular tumour for the diagnosis of urachal MCTLMP and represents the emerging ‘typical’ clinical trajectory of a patient with urachal MCTLMP. Ongoing longitudinal study is required to better understand the longer term behaviour and clinical course of urachal MCTLMP.