Introduction
Urachal carcinoma is a rare malignancy, accounting for less than 1% of all bladder cancers, with adenocarcinoma being the most common histological subtype [1]. It arises from malignant transformation of the urachus, an embryological remnant of the urogenital sinus and allantois. Due to its deep anatomical location and nonspecific clinical presentation, diagnosis is often delayed. Treatment strategies and oncological outcomes largely depend on the stage of the disease at presentation, and surgical excision remains the mainstay of management for localized urachal carcinoma.
We report this case to highlight the aggressive natural history of urachal adenocarcinoma, its propensity for late recurrence despite initial complete resection, and the challenges associated with managing recurrent disease, thereby contributing to the existing limited literature.
Case Report
A 58-year-old woman from Kerala, India presented in 2020 with a three-month history of gross hematuria, dysuria, urinary urgency, and frequency. Ultrasonography demonstrated an echogenic mass adherent to the bladder dome, and routine urinalysis was positive for occult blood. Contrast-enhanced computed tomography (CECT) of the abdomen revealed a solid-cystic mass arising from the dome of the urinary bladder with infiltration of a short segment of jejunum [Fig.1a].
Cystoscopy showed an irregular mass eroding into the bladder wall, and biopsy confirmed mucinous adenocarcinoma. The patient underwent wide local excision with partial cystectomy and segmental small bowel resection. Histopathological examination established the diagnosis of mucinous urachal adenocarcinoma. She remained asymptomatic for three years and subsequent follow-up ultrasonography detected a pelvic mass. Positron emission tomography–computed tomography (PET-CT) revealed a large FDG-avid solid-cystic mass arising from the previously resected bladder dome and encasing both adnexa, without evidence of distant metastasis. Ultrasound-guided biopsy of the right adnexal mass confirmed recurrent mucinous adenocarcinoma.
Patient received six cycles of gemcitabine and cisplatin chemotherapy; however, follow-up CT demonstrated tumor progression. Serum CA-125 was elevated (64 U/mL), while CA 19-9 and carcinoembryonic antigen were within normal limits. She subsequently received eight cycles of CAPE-OX (capecitabine and oxaliplatin) chemotherapy. Repeat PET-CT showed two large FDG-avid solid–cystic lesions with septations
and calcifications, measuring 19×15 cm and 10×15 cm, abutting adjacent structures [Fig.1b]. In view of poor chemoresponsiveness, exploratory laparotomy with wide excision of the recurrent tumor was performed. Intraoperatively, the tumors were adherent to the bladder dome and peritoneum [Fig.2a]. Gross examination revealed two large solid masses with solid-cystic cut surfaces containing mucinous material [Fig.2b].
Microscopic evaluation showed an infiltrating neoplasm composed of tubular and cribriform glands along with signet-ring cells floating in abundant extracellular mucin. The tumor cells exhibited mild to moderate nuclear atypia [Fig.3a-c]. The postoperative period was uneventful, and the patient is currently on follow-up with medical oncology for further management.
Discussion
Urachal carcinoma is an uncommon malignancy, accounting for approximately 0.35-0.7% of all bladder cancers, with adenocarcinoma being the predominant histological subtype [1]. It arises from malignant transformation of remnants of enteric epithelium within the urachus, which extends from the dome of the urinary bladder to the umbilicus. Since its detailed description by Begg in 1931 [2], the understanding of this disease has remained limited, largely due to its rarity and the small number of published case series.
Urachal carcinoma shows a male predominance and commonly presents with hematuria, lower urinary tract symptoms, and, less frequently, mucous or bloody discharge from the umbilicus [1]. Several staging systems have been proposed, of which the Sheldon classification is most widely used in clinical practice [1,3]. Diagnosis relies on clinical evaluation and imaging, with cystoscopy being a mandatory and highly sensitive diagnostic tool, detecting up to 90% of cases [4]. Ultrasonography typically reveals a midline supravesical mass, often with calcifications considered suggestive of urachal origin. Cross-sectional imaging with CT or MRI is valuable for assessing local invasion and distant metastases. The role of 18F-FDG PET/CT appears limited, offering little additional benefit over conventional CT in most cases [4]. Serum tumor markers may aid in disease assessment and prognostication. Elevated carcinoembryonic antigen levels have been reported in nearly 59% of patients and are associated with poorer survival. Increased CA 19-9 and CA 125 levels have also been observed in approximately half of reported cases [4].
Management and outcomes depend largely on disease stage at presentation. Surgical resection remains the cornerstone of treatment for localized urachal carcinoma and typically includes en bloc excision of the urachus and umbilicus with partial or radical cystectomy, often combined with extended bilateral pelvic lymph node dissection. While open surgery remains the most commonly employed approach, laparoscopic and robot-assisted techniques have emerged as safe and feasible alternatives in selected patients [4].
Advanced-stage disease is associated with poor prognosis, and the role of chemotherapy remains limited. Neoadjuvant chemotherapy may be considered in initially unresectable tumors when tumor downstaging could permit complete surgical excision with negative margins. Commonly used regimens include 5-fluorouracil- and cisplatin-based combinations, FOLFOX, and gemcitabine-containing protocols. Selected studies have also explored chemotherapy in combination with cytoreductive surgery, reporting acceptable long-term outcomes. Radiotherapy, however, appears to have minimal efficacy as a local treatment modality. Reported five-year overall survival is approximately 50%, with a cancer-specific survival of around 35% [5]. Recurrence occurs in nearly 15-18% of patients following primary treatment, and systemic chemotherapy may be considered in cases where surgical resection is not feasible [4]. Prognosis is influenced by several factors, including surgical margin status, lymph node involvement, disease stage, distant metastasis, and histopathological subtype [1].
Conclusion
Urachal carcinoma is a rare and aggressive malignancy, and its management remains challenging due to limited evidence and the absence of standardized treatment guidelines. Accurate clinical and radiological staging is essential for planning an individualized treatment strategy and improving outcomes. Complete surgical resection remains the cornerstone of management for non-metastatic disease and can be performed using open, laparoscopic, or robot-assisted approaches. In advanced or metastatic cases, systemic chemotherapy is commonly employed; however, treatment responses are variable and uniform chemotherapy protocols have yet to be established.
Contributors: HS: Concept and manuscript writing; HR: manuscript revision and critical inputs into the final manuscript; MSI, BMB: participated in manuscript writing. HS will act as a study guarantor. All authors approved the final version of this manuscript and are responsible for all aspects of this study.
Funding: None; Competing interests: None stated.
References
- Kumar N, Khosla D, Kumar R, Mandal AK, Saikia UN, Kapoor R, et al. Urachal carcinoma: clinicopathological features, treatment and outcome. J Cancer Res Ther. 2014;10(3):571-574.
- Begg RC. The Urachus: its anatomy, histology and development. J Anat. 1930;64(Pt 2):170-183.
- Sheldon CA, Clayman RV, Gonzalez R, Williams RD, Fraley EE. Malignant urachal lesions. J Urol. 1984;131(1):1-8.
- Loizzo D, Pandolfo SD, Crocerossa F, Guruli G, Ferro M, Paul AK, et al. Current management of Urachal carcinoma: An evidence-based guide for clinical practice. Eur Urol Open Sci. 2022;39:1-6.
- Yu YD, Ko YH, Kim JW, Jung SI, Kang SH, Park J, et al. The prognosis and oncological predictor of urachal carcinoma of the bladder: A large scale multicenter cohort study analyzed 203 patients with long term follow-up. Front Oncol. 2021;11:683190.