Discussion
Acute appendicitis is one of the most common surgical emergencies worldwide affecting approximately 7% of the general population in a lifetime.2 The obstruction of the lumen triggers the inflammation process in the appendix. The most common pathologies associated with lumen obstruction are lymphoid hyperplasia, fecalith, stricture and appendicolith. Stasis and bacterial colonization in the appendix lumen result in appendicitis.

The appendicolith is formed by firm, dense stool and mineral deposits. It is also known as appendiceal calculi, appendiceal enterolith or appendicular lithiasis. Appendicoliths are usually seen in pediatric populations and young adults. They are detected more frequently in men.3 As a nidus for appendicolith, the prevelance of fecalith has been reported as 3% in the population by Jones et al. They also stated that the low-fiber diet has been associated with increased risk of fecalith formation.4

Most appendicoliths are asymptomatic. They are usually detected incidentally with CT in an otherwise normal appendix. Robinowitz et al5 conducted a study on 74 patients with appendicolithiasis. They followed-up patients without surgery, in their first presentation. Fifty-two of these patients (70%) did not return with any complaint. Twenty-two patients were re-admitted with abdominal pain and appendectomy was performed. There were only five patients with inflammed appendix at operation. They concluded that an appendicolith may be associated with increased risk of appendicitis but was not a pure indication for appendectomy. One of our patients presented with classical signs of acute appendicitis. He was diagnosed as acute appendicitis with giant appendicolith in exploration. The appendicolith was found in the base of the appendix. Although it was a very huge stone, there was no signs of gangrene or perforation. We found only two cases of giant appendicolithiasis reported in the literature.6,7

Appendicoliths are seen in about 10% of patients with acute appendicitis.1 They are more frequently associated with appendix perforation and abscess formation.8,9 The appendicolith obstructs the appendix lumen. It also destroys the mucosa with it’s local mass effect. Gangrene in the appendix is inevitable. The patient, in case 2 was operated on due to perforated, gangrenous appendicitis within 24 hours after the beginning of his symptoms. It is important to point out that patients with appendicolithiasis are at increased risk of appendix perforation and abscess formation.

Appendicolith may cause intermittent abdominal pain. It may mimic stone disease of the genitourinary tract. Sometimes it can be difficult to differentiate acute appendicitis from urolithiasis. Both of these pathologies may cause leukocytosis and hematuria. Abdominal findings such as right lower quadrant pain and rebound tenderness can be detected in appendicitis and urolithiasis. Appendicoliths can be detected in abdominal x-ray when they are sufficiently calcified. USG and CT may also help in the diagnosis of an appendicolith. The patient, in case 3 was misdiagnosed as urolithiasis with USG in his first admittance. The definitive diagnosis of appendicitis and appendicolithiasis could be done with abdominal CT.

In conclusion, after widespread use of CT, appendicoliths were encountered more commonly. They have different clinical presentation. While most of the cases are asymptomatic, appendicoliths may also cause appendicitis with serious complications including perforation and intra-abdominal abscess formation.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3072212/