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Urinary Imaging

E3290. Urachal Carcinoma: A Multidisciplinary Approach

Garrana S1,2,  Desouches S1,  Andresen K.1,2 1. University of Missouri, Kansas City, Kansas City, MO; 2. Saint Luke's Hosoital of Kansas City, Kansas City, MO

Address correspondence to S. Garrana (sherief.garrana@gmail.com)

Background Information: Urachal carcinoma, most commonly urachal adenocarcinoma (UCa) is a rare entity occurring at the junction of the urachal ligament and bladder dome, comprising 0.2–0.7% of all bladder cancers. It affects more younger populations than other epithelial cancers, and usually presents with locally advanced disease, with or without metastasis. Evolution of surgical and chemotherapeutic treatments, and recent proposed modifications to the histologic classification and pathologic staging systems, highlight the importance of imaging for a comprehensive diagnostic and management approach.

Educational Goals/Teaching Points: This project illustrates relevant anatomy and the spectrum of imaging features in the subumbilical and perivesical regions. Utility of contrast-enhanced multidetector CT (CECT), MRI, and PET/CT offer promising prospects for UCa. Key imaging features between urachal and transitional urothelial cancer must be distinguished, given the different treatment approach and subsequent morbidity and mortality. After viewing this exhibit, participants will be able to identify key imaging characteristics of UCa, evaluate for locoregional spread of disease, and distinguish Uca from other malignancies that can occur in the perivesical space.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: While ultrasound can be used, CECT, and MRI remain the imaging modalities of choice in evaluation of UCa. Ultrasound may show a midline fluid-filled structure with mixed echogenicity and calcifications. The classic CT feature in 50–70% of patients is a midline heterogeneous mass anterosuperior to the bladder dome with areas of low attenuation, correlating to mucin pools on gross pathology. Calcifications, usually peripheral, are seen in up to 70% of patients and are pathognomonic. The bladder dome is usually involved, with irregular wall thickening and extravesical extension involving Retzius space. Identification of advanced disease features such as abdominal wall involvement, peritoneal spread, and regional node or distant metastasis is imperative for treatment planning and prognosis. MRI is useful for evaluation of mucin-producing tumors. Increased FDG uptake on PET/CT has been reported, however its role in routine evaluation and management of UCa has not yet been studied.

Conclusion: Despite its rare incidence, UCa continues to pose diagnostic and therapeutic challenges, commonly presenting with locally advanced or metastatic disease. Efforts over the past several decades have yielded advances in surgical techniques. Imaging modalities offer promising prospects in advancing UCa evaluation and management. Radiologists should readily identify key imaging findings guiding preoperative clinical staging and surgical planning, assessing chemotherapy response, and posttreatment surveillance. A multidisciplinary approach between the urologist, pathologist, and radiologist, with continued correlation of surgical, pathologic and imaging findings offers the best comprehensive approach for diagnostic accuracy and optimal management.