This child has a Meckel's diverticulum, which is a true diverticulum containing all layers of the gastronintestinal tract (epithelium, lamina propria, submucosa, muscularis propria/externa, and adventitia).
Meckel's diverticulum is the most common congenital GI abnormality. It forms a blind outpouching in the ileum, and is caused by incomplete closure of the vitelline duct, also known as the omphalomesenteric duct or yolk stalk, which is typically closed by 7 weeks gestation. It is considered a true diverticulum, which includes all layers, including muscularis propia and adventitia (in comparison to a false diverticulum, which do not involve all layers, typically sparing the muscularis propia and adventitia). Although it is typically asymptomatic, it may present with GI bleeding or small bowel obstruction. It is often associated with the rules of 2: occurring before 2 years of age, present in 2% of population, located 2 feet from ileocecal valve, it is 2 times as common in men, it is symptomatic in only 2% of patients, and is 2 inches in length.
Martin et al. discuss the common presentation, differential diagnosis, and treatment of Meckel's diverticulum. Technetium-99m pertechnetate scan is a diagnostic modality which locates ectopic gastric tissue and is commonly used to diagnose Meckel's diverticulum. Ectopic tissue is only present in approximately 50% of cases, and only 60-85% of those cases contain gastric tissue, so the Technetium-99m scan may miss patients without ectopic gastric tissue. The treatment of Meckel's diverticula is surgical removal.
Kotecha et al. discuss the clinical presentation and the challenges of diagnosis of Meckel's diverticulum with imaging. Common complications of Meckel's include peptic ulceration, gastrointestinal obstruction, inflammation, and bowel perforation. Rare complications include neoplastic changes and giant diverticula. Meckel's may be found incidentally during imaging, if this happens, then a normal appendix should be identified and documented in order to differentiate the two.
Figure A shows a technetium-99m pertechnetate scan with increased activity above the bladder, indicating a Meckel's diverticulum.
Answer 2: Meckel's diverticulum is 2 times as common in males than females.
Answer 3: Meckel's diverticulum is typically found 2ft from the ileocecal valve around the ileum.
Answer 4: Meckel's diverticulum is a remnant of the vitelline or omphalomesenteric duct; the urachus is a remnant of the allantois.
Answer 5: Meckel's diverticulum is only symptomatic in 2% of patients.
Martin JP, Connor PD, Charles K. Meckel's diverticulum. Am Fam Physician. 2000 Feb 15;61(4):1037-42, 1044. Review. PubMed PMID: 10706156.
PMID:10706156 (Link to Abstract)
Kotecha M, Bellah R, Pena AH, Jaimes C, Mattei P. Multimodality imaging manifestations of the Meckel diverticulum in children. Pediatr Radiol. 2012 Jan;42(1):95-103. doi: 10.1007/s00247-011-2252-7. Epub 2011 Oct 9. Review. PubMed PMID: 21984316.
PMID:21984316 (Link to Abstract)