Bladder-Adherent Primary Appendiceal Carcinoma Masquerading as a Carpeting Rectal Lesion Detected by a Fecal Immunochemical Test: A Case Report.

This is a rare case of appendiceal carcinoma invading the rectum and presenting as a positive screening fecal immunochemical test in an asymptomatic individual. We effectively demonstrate the use of preoperative MRI to identify the appendiceal origin of the tumor, as well as to demonstrate the extent of tumor spread, which assisted with operative management and treatment planning.