Exploring the Enigma of a Urachal Mucinous Cystic Tumor of Low Malignant Potential (MCTLMP): A Case Report and Literature Review.

Mucinous urachal neoplasms are rare and can present as benign cystadenomas, mucinous cystic tumors of low malignant potential (MCTLMPs), or invasive adenocarcinomas. MCTLMPs occupy a borderline category characterized by mild-to-moderate atypia and papillary/villous architecture without stromal invasion. Here, we describe a 54-year-old male patient who presented with persistent dysuria and was found to have a vesicourachal diverticulum. Surgical management involved a robot-assisted partial cystectomy with complete excision of the urachal remnant. Histopathologic examination revealed a multiloculated cystic lesion lined by mucin-producing epithelium, confirming an MCTLMP; immunohistochemical staining demonstrated intestinal differentiation (CK20+/CK7-/CDX2+) and absence of invasive features. p53 demonstrated wild-type expression, indicating no significant molecular alterations. The early postoperative course was uneventful, with no complications such as infection or urinary leakage. At the one-year follow-up, the patient experienced persistent urinary urgency, suprapubic discomfort, and scrotal pain, indicative of lower urinary tract dysfunction secondary to surgical intervention. No recurrence has been observed. This case underscores the importance of accurate histopathological evaluation, complete surgical resection, and vigilant long-term surveillance to prevent progression of urachal mucinous tumors. Further research into molecular markers may refine prognostication and guide future therapeutic strategies for these rare neoplasms.