[A Case of Appendiceal Mucinous Carcinoma with Bladder Invasion Developed from Abscess-Forming Appendicitis, Which Was Curatively Resected after Chemotherapy].

The patient was a 35-year-old man who saw his first doctor with the chief complaint of painful urination. A contrast- enhanced CT scan of the abdomen revealed a diagnosis of abscess-forming appendicitis with inflammatory spread to the bladder, and conservative treatment was decided. Since antibiotic treatment failed to reduce the size of the abscess, he underwent surgery. The bladder wall was highly inflamed, only appendectomy was performed. Pathology revealed appendiceal mucinous carcinoma invading the bladder, so he was referred to our department. Because a total cystectomy was required for curative resection and there was concern about seeding associated with the initial surgery, he was judged to be unresectable, and received chemotherapy. After 6 courses of CAPOX+bevacizumab therapy, he was able to have a bladder- sparing curative resection because of the absence of distant metastasis and shrinkage of the tumor. He remains stable without recurrence 6 months after surgery. We herein report, with some discussion of the literature, this case of bladder-invading appendiceal mucinous carcinoma arising from abscess-forming appendicitis, for which a curative resection was possible after chemotherapy.