Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract, resulting from incomplete obliteration of the omphalomesenteric (vitelline) duct. Defined by the 'rule of 2s': found in 2% of the population, approximately 2 feet (60 cm) proximal to the ileocecal valve, approximately 2 inches (5 cm) in length, 2% become symptomatic, and most commonly presents before age 2. Approximately 50% contain ectopic gastric mucosa — diagnostic on Tc-99m pertechnetate scintigraphy. On CT, it presents as a blind-ending tubular structure on the antimesenteric border of the ileum or with inflammation findings. Complications: bleeding (peptic ulceration from ectopic gastric mucosa), diverticulitis, intestinal obstruction, intussusception, and perforation.
Age Range
0-40
Peak Age
20
Gender
Male predominant
Prevalence
Uncommon
Meckel's diverticulum embryologically results from failure of obliteration of the omphalomesenteric (vitelline) duct. In normal development, this duct completely obliterates by the 5th-7th gestational week; incomplete obliteration produces various anomalies along a spectrum: complete patent duct (omphaloileal fistula), fibrous band (Meckel band), umbilical sinus, or diverticulum. Meckel's diverticulum is a 'true diverticulum' because it contains all layers of the bowel wall (mucosa, submucosa, muscularis propria, serosa) — distinguishing it from acquired diverticula (pseudodiverticula, herniation of mucosa and submucosa only). It locates on the antimesenteric border of ileum because the omphalomesenteric duct originates from the antimesenteric surface of the primitive midgut. With ectopic gastric mucosa, hydrochloric acid secretion causes peptic ulceration in surrounding ileal mucosa — leading to bleeding or perforation. Tc-99m pertechnetate scintigraphy detects ectopic gastric mucosa because pertechnetate ion is taken up by gastric parietal cells and mucin-secreting cells — this physiological uptake mechanism enables detection of ectopic gastric mucosa outside the normal stomach. On CT, uncomplicated Meckel's diverticulum is often incidentally detected; in complicated cases, surrounding fat infiltration, wall thickening, and inflammatory changes may mimic acute appendicitis.
Focal radiotracer uptake in right lower quadrant or periumbilical area on Tc-99m pertechnetate scintigraphy — pathognomonic finding for ectopic gastric mucosa. Appears simultaneously with normal stomach uptake and increases in intensity over time.
On Tc-99m pertechnetate scintigraphy, focal radiotracer uptake in the right lower quadrant or periumbilical area is observed — reflecting ectopic gastric mucosa. Uptake appears simultaneously with normal stomach uptake. Sensitivity is 85-90% in children, 60-70% in adults. Cimetidine pretreatment increases pertechnetate retention, improving sensitivity.
Report Sentence
Focal radiotracer uptake in the [right lower quadrant/periumbilical] area on Tc-99m pertechnetate scintigraphy, consistent with Meckel's diverticulum containing ectopic gastric mucosa.
On CT, a blind-ending tubular or saccular structure on the antimesenteric border of the distal ileum is observed. In uncomplicated cases, thin-walled with fluid or gas content. In complicated cases (Meckelitis), wall thickening, enhancement, surrounding fat infiltration, and free fluid accompany.
Report Sentence
A [size] mm blind-ending tubular structure on the antimesenteric border of the distal ileum is identified, consistent with [uncomplicated/complicated] Meckel's diverticulum.
With active bleeding, contrast extravasation into diverticulum lumen or adjacent ileal lumen is observed in arterial phase. This finding is detected in life-threatening GI bleeding and indicates emergency surgical/angiographic intervention.
Report Sentence
Contrast extravasation in the [location] ileum on arterial phase, suggesting active GI bleeding — EMERGENCY intervention required.
Meckel's diverticulitis findings: diverticulum wall thickening (>3 mm), wall enhancement, surrounding mesenteric fat infiltration, reactive fluid, and regional LAP. These findings may be difficult to differentiate from acute appendicitis — however, lesion location in distal ileum separate from appendix suggests diagnosis.
Report Sentence
Wall thickening, enhancement, and surrounding fat infiltration in a diverticular structure in the distal ileum, consistent with Meckel's diverticulitis.
Meckel's diverticulum may serve as lead-point for intussusception. CT shows 'target sign' or 'sausage sign' — concentric soft tissue rings with mesenteric fat within telescoping bowel segment.
Report Sentence
Intussusception with concentric ring pattern in the [location] ileum, potentially originating from Meckel's diverticulum.
On ultrasonography, a blind-ending cystic or tubular structure related to small bowel may be observed in the right lower quadrant. In complicated cases, surrounding hyperechoic fat infiltration and free fluid accompany. Frequently used for initial assessment in pediatric patients.
Report Sentence
On US, a blind-ending tubular structure related to small bowel in the right lower quadrant, suggestive of Meckel's diverticulum.
Criteria
Gastric parietal and chief cells in diverticulum mucosa. ~50% of cases.
Distinct Features
Tc-99m pertechnetate positive. Peptic ulceration and bleeding risk. Most common complication cause in children.
Criteria
Pancreatic acinar/ductal tissue in diverticulum. Rarer (5%).
Distinct Features
Tc-99m pertechnetate negative. Pancreatitis-like complications rare.
Criteria
Clinical complications of Meckel's diverticulum. Surgical indication.
Distinct Features
Wall thickening, fat infiltration, intussusception, or contrast extravasation on CT. May mimic acute appendicitis.
Distinguishing Feature
Appendicitis blind-ending structure from cecum, right iliac fossa; Meckel antimesentric diverticulum from ileum, ~60 cm proximal to ileocecal valve
Distinguishing Feature
Crohn's segmental ileal wall thickening, skip lesions, fistula; Meckel focal diverticular structure, no segmental involvement
Distinguishing Feature
Adhesive obstruction transition point, dilated proximal-collapsed distal; Meckel intussusception or band obstruction — diverticular structure identifiable
Distinguishing Feature
Acquired colonic diverticulitis in left colon, multiple diverticula; Meckel ileal, solitary, antimesenteric, congenital
Urgency
emergentManagement
surgicalBiopsy
Not NeededFollow-up
no-follow-upComplicated Meckel's diverticulum is a surgical emergency — diverticulectomy or segmental ileum resection is performed. In bleeding cases, angiographic embolization may be attempted first, surgery if unsuccessful. Prophylactic resection of incidentally detected asymptomatic Meckel's diverticulum is controversial — generally recommended for <50 years, male sex, >2 cm size, and abnormal tissue on palpation. Tc-99m pertechnetate scintigraphy should be the first-line diagnostic test for investigating GI bleeding in children. In adults, CT angiography and mesenteric angiography are used for active bleeding localization.
Meckel's diverticulum is usually asymptomatic. Complications include bleeding (ectopic gastric mucosa), diverticulitis, obstruction, and intussusception. Surgical resection (diverticulectomy) is performed in symptomatic cases.