Appendiceal mucocele of mucinous cystadenocarcinoma with a cutaneous fistula

We report a novel case of cystadenocarcinoma forming an appendiceal mucocele with development of a skin fistula. The patient was a 75-year-old Japanese woman who originally presented with a skin ulcer on the right flank (inferior to the ribs and superior to the iliac bone) with mucus discharge. The serum concentration of carcinoembryonal antigen was elevated (57.4 ng/ml). Ultrasonography and computed tomography demonstrated a cystic mass with septations in the right iliac fossa. Fistulography from the skin ulceration showed a communication via the fistula to the caecum. A right hemicolectomy and enbloc resection of the skin fistula was performed. The histological findings revealed a well-differentiated mucinous cystadenocarcinoma of the appendix. The patient has been alive for 7 years following surgery without any sign of recurrence. This report is of interest as it demonstrates that tumour rupture to the extraperitoneal space could result in a good outcome by preventing the development of pseudomyxoma peritonei.