Abstract
Introduction: Urachal adenocarcinoma is one of the rare bladder malignancies. The pathogenesis and behaviour of the disease is not fully known except for its aggressive nature especially with positive margins, advanced stage and regional lymph node involvement.
Case report: Here we report a case of 50-year-old male patient who o our hospital with chief complaints of swelling below the umbilicus with active haematuria and on physical examination, a hard mass measuring 5x 3 cm was felt below the umbilicus.
Contrast enhanced computed tomography (CECT) scan revealed a heterogeneously enhancing lesion occupying the dome of bladder with loss of fat planes involving the anterior abdominal wall muscles and at one location in the mesentery.
Laparotomy revealed a fleshy mass arising from the dome of bladder with blood clots. En bloc removal of umbilicus with soft tissue underneath and partial cystectomy was done. Intraoperatively a mass measuring 8x6 cm was seen extending from the umbilical skin till bladder dome. In addition, multiple peritoneal as well as mesenteric deposits were noted.
Histopathology confirmed the diagnosis of adenocarcinoma with positive margins along with mesenteric and peritoneal metastasis. The tumour was staged as Sheldon/ Mayo stage/ Tumour, Node, Metastasis (TNM) IV and started under palliative chemotherapy which included cisplatin and gemcitabine. After 2 cycles of chemotherapy, lung metastasis was detected and the patient succumbed to his illness.
Conclusion: This case of urachal adenocarcinoma has been put up primarily to highlight the way of locoregional and distant metastatic spread, thereby adding contribution to the already existing sparse literature. The patient had peritoneal spread along with less frequently detected mesenteric involvement at the time of presentation and rapidly developed pulmonary metastasis. As many of its behaviours remain hidden, case series and case reports with shared experiences of surgeons, urologists and pathologists are essential to unravel its hidden behaviours.

Key words: urachal adenocarcinoma, pulmonary metastasis, Sheldon staging, bladder dome