appendicolith
An appendicolith is a calcified deposit within the appendix. They are present in a large number of children with acute appendicitis and may be an incidental finding on an abdominal radiograph or CT. Incidence may be increased among patients with a retrocecal appendix. Overall they are seen in 10% of patients, with 90% subsequently going on to develop appendicitis .
Pathology
Although the cause of appendicolith formation is uncertain, some case reports have mentioned an ingested foreign body or a dislodged gallstone eroding through the gallbladder as possible etiologies.
Radiographic features
If identified on ultrasound, an appendicolith will appear cast an acoustic shadow. On abdominal radiograph or CT, a high attenuation stone may be seen in the right iliac fossa. CT is more sensitive than plain film. Up to 25% show laminated calcification.