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.

Keywords: Appendix cancer; appendiceal diverticular disease; case report; diverticulosis.

Figure 1

CT scan of abdomen demonstrating peri-appendiceal abscess with perforated appendicitis.

Figure 2

Intra-operative laparoscopic image of appendiceal phlegmon.

Figure 3

Acquired diverticulum at the appendiceal tip with deficient muscularis propria (black arrow). (H & E stain, low power, magnification x2).

Figure 4

Well-differentiated appendiceal adenocarcinoma (black arrow) arising adjacent to normal appendiceal mucosa. (H & E stain, low power, magnification x4).