Giant Colonic Diverticulum

Abstract

Editor's Note.-Everyone who has taken the course in radiologic pathology at the Armed Forces Institute of Pathology (AFIP) remembers bringing beautifully illustrated cases for accession to the Institute. In recent years, the staff of the Department of Radiologic Pathology has judged the ''best cases'' by organ system, and recognition is given to the winners on the last day of the class. With each issue of RadioGraphics, one or more of these cases are published, written by the winning resident. Radiologicpathologic correlation is emphasized, and the causes of the imaging signs of various diseases are illustrated.

A Rare Case Presentation of a Perforated Giant Sigmoid Diverticulum

“…Hughes and Greene in 1953 reported the first radiological diagnosis and the first case in the English language literature and described it as a case of “solitary air cyst” arising from the antimesenteric border of the sigmoid colon. Since that time, case reports have appeared in the literature describing this condition with various names such as “giant gas cyst,” “giant sigmoid diverticulum,” “giant colonic diverticulum,” or “intestinal gas cyst” [1, 2, 5, 6, 9, 13, 14, 17]. …”

“…In rare cases, the wall may contain other substances or disease, including amyloid [17], lymphoma of mucosa-associated lymphoid tissue (MALT) [8], and urothelium [4, 15]. …”

“…A pseudodiverticulum of mucosa and submucosa forms through muscularis whose communication with the bowel lumen becomes so narrowed by inflammation that a ball-valve/flap-valve mechanism is created whereby gas can enter the serosa-lined cyst as intraluminal pressure increases but cannot exit the diverticulum (a one-way communicating stalk) [1, 7–9]. Narrowing of the diverticulum neck from inflammation creates a flap-valve mechanism that traps gas in the diverticular cavity as intraluminal pressure in the bowel increases during defecation [8, 10, 12, 17]. Trapped air is vented intermittently and along with differences in colonic pressures leads to fluctuations in the GCD size [7, 12].…”

“…First, the neck or stalk of the diverticulum becomes obliterated by chronic inflammation, and then gas is produced from the organisms located within the cyst, which progressively distends and enlarges the diverticulum [8, 9, 17]. The more accepted theory has been the “ball-valve theory” for several reasons.…”

CT findings of misleading features of colonic diverticulitis

“…Giant diverticulum, defined as a colonic diverticulum measuring 4 cm in size or larger, is a rare complication of this common disease with fewer than 150 cases reported in the literature [26]. Preoperative diagnosis requires a high degree of suspicion and needs to be differentiated from sigmoid volvulus, caecal volvulus, intestinal duplication cyst, pneumatosis cystoides intestinalis, and similar conditions [27].…”