Identification of Rare EIF3E::RSPO2 Fusion in Recurrent and Aggressive Urachal Adenocarcinoma.

INTRODUCTION: Urachal cancer (UC) is a rare genitourinary malignancy arising from the urachus, an embryonic remnant of the placental allantois. Its diagnosis remains ambiguous with late-stage cancer detection and represents a highly aggressive disease. Due to its rarity, there is no clear consensus on molecular signatures and appropriate clinical management of UC.

CASE REPORT: We report a 45-year-old man with recurrent urachal adenocarcinoma (UA) treated with cystectomies, chemotherapy, and radiotherapy. The patient initially presented with hematuria and abdominal pain. Imaging revealed a nodular mass arising from the superior wall of the urinary bladder and extending to the urachus. Biopsy results suggested moderately differentiated UA with muscle layer involvement. The tumor recurred after 20 months, following which, another partial cystectomy was performed. Repeat progression was noted indicating highly aggressive disease. Targeted next-generation sequencing revealed the presence of EIF3E::RSPO2 fusion, along with BRAF and TP53 mutations, and EGFR gene amplification. This is the first case reporting the presence of this fusion in UA. Palliative medication and radiotherapy were administered to manage the disease.

CONCLUSION: Current treatment modality of surgery may be effective in the early stages of recurrent UA; however, a standard chemotherapy and radiotherapy regimen is yet to be determined for advanced stages. The detection of the rare EIF3E::RSPO2 fusion warrants further studies on the significance of this variant as a possible therapeutic target for improved clinical management.