Surgical treatment of urachal adenocarcinoma with lung metastasis: A case report and literature review.

Arising from the urachal epithelial lining, the urachal carcinoma is a rare tumor, which accounts for 0.35%-0.7% of all bladder cancers. Urachal carcinoma has a higher predilection in men with median age around 50-60 years old. The most common clinical symptom is intermittent painless gross hematuria, and less-reported presentations include suprapubic mass, dysuria, lower abdominal pain, and frequent urination. The pathological study reveals that most cases (90%) are categorized as an intestinal adenocarcinoma subtype, while other morphological variants, including mucinous, enteric, signet ring cell subtype, not otherwise specified (NOS), squamous cell carcinoma, urothelial carcinoma, sarcoma, small cell carcinoma, and undifferentiated carcinoma, totally account for about 10%. The urachal carcinoma occurs mostly in the lower segment of urachal tube and bladder dome or anterior wall. However, due to the classically silent nature of the early lesions and high malignancy, urachal carcinoma patients are commonly diagnosed in advanced stage. Treatment modalities for local recurrence or metastatic urachal cancer include surgery and chemotherapy (cisplatin and 5-FU based-chemotherapy). Meanwhile, the EGFR-, PD-L1-, and MEK-targeted therapies in the metastatic urachal carcinoma cases showed satisfactory response. We presented a rare case of Sheldon stage IVB urachal adenocarcinoma with pulmonary metastasis, and the patient had no progression of disease 6 months following surgical treament without chemoradiotherapy.