Appendiceal diverticulosis: a harbinger of underlying primary appendiceal adenocarcinoma?

Abstract

Diagnosis of primary appendiceal adenocarcinoma (PAA) is hindered by its rarity and largely asymptomatic nature. Appendiceal diverticulosis (AD) is equally rare. We report an unusual case of PAA presenting with perforated appendiceal diverticulitis, and discuss a review of the literature about its association, and its surgical and pathological implications. A middle-aged man was admitted with right iliac fossa (RIF) pain and a corresponding tender abdominal mass for 5 days. Computerised tomography (CT) scan demonstrated a thickened appendix with 3 cm abscess at its base. During laparoscopic appendicectomy, the appendiceal phlegmon was adhered to the surrounding bowel. Histology showed a perforated diverticulum near the appendiceal tip, and a primary appendiceal well-differentiated adenocarcinoma located proximal to it with clear margins. Up to 48% of ADs are associated with appendiceal neoplasms, but its coexistence with PAA is reported in fewer than ten instances worldwide. Obstructing appendiceal tumours, by raising intraluminal pressure, can predispose to AD formation. Intestinal-type PAA is often managed like its colorectal counterpart, although controversies about management of PAA in a perforated AD remain. Recognition of the association of AD and PAA is critical to ensure meticulous oncological resection and histological examination.

A case of laparoscopic appendectomy for appendiceal bleeding

“…True diverticula are thought to be related to deformity due to the duplication of the appendix, a remnant of the yolk duct, or adhesions [ 4 ], but they occur congenitally and the details of their cause have not yet been clarified. Pseudodiverticula are thought to be formed by increased appendiceal luminal pressure, and pseudodiverticula account for more than 95% of all diverticula [ 5 ]. Therefore, the perforation rate is high in appendiceal diverticulitis, and complicated appendicitis often follows.…”

Appendiceal Diverticulitis in a Young Female Diagnosed on Pathology after Laparoscopic Appendectomy for Acute Appendicitis

“…Appendiceal diverticulitis has been shown to be more than four times as likely to perforate compared with acute appendicitis, increasing mortality 30-fold compared with simple appendicitis [ 2 , 8 ]. Therefore, correct diagnosis and urgent management with antibiotics and appendectomy are currently favoured with laparoscopy being the preferred approach [ 12 , 13 ]. In contrast to diverticulitis of the colon or small bowel, no large series demonstrating successful nonoperative management of appendiceal diverticulitis are available, and this is most likely due to the fact that appendicitis and appendiceal diverticulitis are difficult to distinguish on imaging [ 14 ].…”

“…It should be recognized that diverticula of the appendix are also associated with an increased risk of appendiceal neoplasms including carcinoid tumors, adenocarcinoma, and mucinous adenomas (pseudomyxoma peritonei) [ 4 ]; strengthening the argument for appendectomy [ 13 , 15 ].…”

Imaging in Appendicular Diverticulosis with Appendicitis

“…AD is a rare condition occurring in 0.004 (2.1%) of appendicectomies. 1 It was first described by Kelynack in 1893. 2 These are protrusions of the mucosa and submucosa through muscularis defect and hence are pseudodiverticula.…”