Giant appendicolith: Rare finding in a common ailment.

Acute appendicitis is one of the commonest surgical emergencies worldwide. There is considerable variation in prevalence of appendicoliths with appendicitis. Most of the patients with appendicoliths are asymptomatic and they are not pathognomic for acute appendicitis. However, appendicoliths show increased association with perforation and abscess formation. Appendicolith are quite common, being present in 3% of general population and in nearly 10% cases of appendicitis. However, giant appendicoliths measuring over 2 centimeters (cms) are extremely rare. Computed Tomography (CT) has increased their pre-operative diagnosis considerably. Use of spectral analysis can give us the details of composition of the stone pre-operatively. We present a young male diagnosed pre-operatively on Non-Contrast Computed Tomography (NCCT) to have a giant calcium struvite appendicolith. On laparoscopy he had a 3 cm stone and an incidental Meckel's diverticulum and underwent appendectomy. The case is presented for the unique size of the appendicolith alongwith review of literature.

INTRODUCTION

Acute appendicitis, one of the commonest surgical emergencies, affects nearly 7% of the world's population and accounts for about 1% of all surgical operations. Faecoliths formed by mineral deposits layered with faecal debris and lodged in the appendix are called appendicoliths. The prevalence of faecoliths in the general population is 3%, and appendicoliths are seen in 10% cases of acute appendicitis. However, giant appendicoliths (>2 cm) are extremely uncommon.[123]

CASE REPORT

A 25-year-old male presented to us with pain in the right flank for 1 day. He had history of ureterorenoscopic removal of a right ureteric stone 1 year earlier. His vital signs, general physical examination and abdominal examination revealed no abnormality. Urinalysis was normal, and abdominal ultrasound raised a suspicion of small calculi in the right kidney. Non-contrast computed tomography (NCCT) abdomen revealed a few subcentimetric calculi in both kidneys without hydronephrosis or hydroureter. However, it also revealed a large appendicolith of 2.5 × 2.1 cm2 size. [Figure 1c and d] (mineral core), composed mainly of calcium and struvite on spectral analysis [Figure 1a and b]. His routine investigations were essentially normal. He underwent laparoscopic appendectomy using a 10-mm supra-umbilical camera port and two 5 mm ports at the supra-pubic region and the left iliac fossa, respectively. A pre-ileal appendix was found hidden in flimsy adhesions posterior to the terminal ileum. An incidental Meckel's diverticulum was also found [Figure 1f], which was not pathological and was left alone. The mesoappendix was cut using Harmonic scalpel (Johnson and Johnson make) and the appendix was cut at the base between ligatures [Figure 1e]. It was removed using a glove bag after enlarging the supra-umbilical incision because of the large stone size — 2.5 cm × 3.0 cm [Figure 1g and h]. The patient had an uneventful recovery.

Figure 1

NCCT abdomen (a and b) The CT spectral analysis of the appendicolith shows the highest peak of the histogram corresponding to struvite-calcium (c) Multiplanar reconstruction (MPR) coronal image showing appendicolith 2.50 cm size (longitudinal) (d) Axial image showing appendicolith 2.10 cm size (transverse) (e-h) Laparoscopic appendectomy, procedure, specimen and appendicolith (e) Multiple ligations of base of appendix (f) Meckel's diverticulum (g) Size of appendicolith 3 cm on longest axis (h) Size of appendicolith 2.5 cm on the perpendicular axis

DISCUSSION

Acute appendicitis was first reported by Fitz in 1886, and Wangensteen and Bowers proposed the theory of an obstructive component as a causative factor in 1937. Other proposed aetiologies include lymphoid hyperplasia, constipation, trauma, diet, genetic predilection, hypersensitivity and mucosal ulceration. Appendicoliths are usually seen in children and young adults. They are more common in males and in the retrocaecal appendix. A low-fibre diet increases the risk of faecolith formation.[123]

Appendicolith on plain abdominal x-ray is a reliable sign of appendicitis (70%). However, computed tomography (CT) is more sensitive, detecting even non-calcified faecoliths. On CT, appendicoliths appear as laminated bodies with gas in centre or homogenous opacity. When symptomatic, they carry 90% probability of acute appendicitis and 50% higher risk of perforation and abscess formation. Some authors have found good correlation (65-100%) between faecoliths on CT and appendicitis, while others have not.[12]

In a retrospective review by Lowe et al., an appendicolith detected on CT had a sensitivity of 65%, specificity of 86%, and positive predictive value of 74% for the diagnosis of appendicitis.

Despite appendicoliths being common, a giant appendicolith (>2 cm) is extremely rare and only sporadically reported. The largest appendicolith we found was 2.3 cm (2 cm on CT).[3] Others include a 2.1 cm appendicolith reported by Garg and a 2.2 cm stone by Kaluarachchi.

Our case is probably the largest documented stone (3 × 2.5 cm2) and the first whose chemical composition has been determined preoperatively by spectral analysis.

Financial Support and Sponsorship

Nil.

Conflicts of Interest

The authors declare that they do not have any conflict of interest. The authors have not received any resources from a third party, directly or indirectly, to complete this work.