Appendiceal Adenocarcinoma Presenting as a Rectal Polyp

Abstract

Appendiceal adenocarcinoma typically presents as an incidentally noted appendiceal mass, or with symptoms of right lower quadrant pain that can mimic appendicitis, but local involvement of adjacent organs is uncommon, particularly as the presenting sign. We report on a case of a primary appendiceal cancer initially diagnosed as a rectal polyp based on its appearance in the rectal lumen. The management of the patient was in keeping with standard practice for a rectal polyp, and the diagnosis of appendiceal adenocarcinoma was made intraoperatively. The operative strategy had to be adjusted due to this unexpected finding. Although there are published cases of appendiceal adenocarcinoma inducing intussusception and thus mimicking a cecal polyp, there are no reports in the literature describing invasion of the appendix through the rectal wall and thus mimicking a rectal polyp. The patient is a 75-year-old female who presented with spontaneous hematochezia and, on colonoscopy, was noted to have a rectal polyp that appeared to be located within a diverticulum. When endoscopic mucosal resection was not successful, she was referred to colorectal surgery for a low anterior resection. Preoperative imaging was notable for an enlarged appendix adjacent to the rectum. Intraoperatively, the appendix was found to be densely adherent to the right lateral rectal wall. An en bloc resection of the distal sigmoid colon, proximal rectum and appendix was performed, with pathology demonstrating appendiceal adenocarcinoma that invaded through the rectal wall. The prognosis in this type of malignancy weighs heavily on whether or not perforation and spread throughout the peritoneal cavity have occurred. In this unusual presentation, an en bloc resection is required for a complete resection and to minimize the risk of peritoneal spread. Unusual appearing polyps do not always originate from the bowel wall. Abnormal radiographic findings adjacent to an area of gastrointestinal pathology may signify locally advanced disease from a surrounding organ that secondarily involves the gastrointestinal tract. These findings warrant further investigation prior to any intervention to ensure appropriate treatment.

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

“…Previous studies have reported that preoperative imaging techniques are ineffective in accurately exhibiting the origin and extent of appendiceal adenocarcinoma [ 1 ], often necessitating surgical intervention for diagnostic and therapeutic purposes [ 1 , 2 , 6 ]. Here, we demonstrate that preoperative staging MRI was, in fact, crucial in identifying the appendiceal origin of this carcinoma and its invasion to the urinary bladder and rectum.…”

“…Although right lower quadrant abdominal pain mimicking acute appendicitis is more commonly seen as the primary presenting symptom [ 2 ], irritative urinary symptoms such as increased frequency, dysuria [ 1 , 4 ], hematuria, and fecaluria can occur [ 5 ]. The prognosis depends on the extent of organ invasion and spread of the tumor in the peritoneal cavity, as well as the type of surgery performed [ 6 ]. The preoperative determination of the origin and extent of appendiceal carcinoma is challenging [ 1 ].…”

“Obscure” Appendiceal Orifice Polyps Can Be Challenging to Identify by Colonoscopy

“…Prognosis is also worse among patients presenting with appendiceal malignancy. One of the reasons for this is related to the higher propensity of appendiceal cancer to spread through the lymphatic system [12].…”