We report a case of an appendix carcinoma invading the urinary bladder
. In contrast to other bowel tumors invading the bladder, history and
symptoms were consistent with a primary bladder tumor. This is due to
the unique anatomical position of the appendix where the tumor did not
hinder passage of bowel contents or cause melena. Findings an physica
l examination as well as diagnostic imaging and transurethral resectio
n were inconclusive. Consideration of local progression of an appendix
carcinoma is an important differential diagnosis. In contrast to othe
r vesical or extravesical T-4 tumors, the appendix carcinoma offers a
good chance for resection en bloc by right-sided hemicolectomy and par
tial cystectomy.