Urachal mucinous cystic tumor of low malignant potential in a polymorbid female: a case report and review of the literature

Neoplasms of the urachus are exceedingly rare, representing 0.17% of all bladder cancers. The mucinous cystic tumor of low malignant potential (MCTLMP) subtype is particularly rare with just 25 previous cases reported in the literature. Although rare, MCTLMPs are important to identify due to potential devastating complications and good cure rates with surgical removal. We present a 43 year old female with a nuanced constellation of comorbidities and confirmed MCTLMP following a workup for abdominal pain and irritative lower urinary tract symptoms. Notably, this tumor did not change in size over a 3-year course of serial imaging prior to surgical excision. This urachal MCTLMP represents roughly the 26th and one of the smallest of its subtype reported in the literature. This case illustrates the diagnosis and management of this rare urachal MCTLMP. Individual patient medical history, clinical considerations, and neoplasm characteristics are examined. Although rare, the potential for increased malignancy and potential complications necessitates surgical management and further investigation by the academic community.

Urachal Mucinous Cystic Tumor of Low Malignant Potential with Concurrent Sigmoid Colon Adenocarcinoma

Urachal mucinous tumors are rare neoplasms with behaviour that can range from relatively benign to malignancy that can spread distantly or throughout the peritoneum as pseudomyxoma peritonei or peritoneal carcinomatosis. Here we describe a unique case of urachal mucinous cystic tumor of low malignant potential confined to an intact cyst at the dome of the urinary bladder, without rupture or peritoneal spread. The urachal mucinous tumor was an incidental finding on a staging CT scan performed for sigmoid colon adenocarcinoma. We believe that this case illustrates a potential diagnostic pitfall which could have prognostic and therapeutic implications. Due to the intestinal phenotype of these neoplasms, a urachal tumor of low malignant potential could be mistaken for metastatic spread from a colonic adenocarcinoma in the rare situation such as this case, where the two neoplasms occur concurrently.

Mucinous Cystadenoma of the Urachus and Review of Current Classification of Urachal Mucinous Cystic Neoplasms

Urachal neoplasms are uncommon and represent a minor portion of bladder tumors. According to the recently updated World Health Organization classification (2016), these tumors are classified as adenomas, adenocarcinomas, nonglandular neoplasms, and mixed carcinomas. The mucinous cystic neoplasms represent a small percentage of urachal tumors with morphologic spectrum ranging from benign mucinous cystadenoma to borderline mucinous cystic tumor of low malignant potential and to malignant mucinous cystadenocarcinoma. Benign urachal mucinous cystic adenomas are exceedingly rare, and only a few cases have been reported in the literature to date. The goal of this review is to summarize the clinical features, histopathologic characteristics, treatment, and prognosis of urachal mucinous cystadenoma in light of differentiating them from mucinous cystic tumor of low malignant potential and mucinous cystadenocarcinoma.