Large Enterolith Complicating a Meckel Diverticulum Causing Obstructive Ileus in an Adolescent Male Patient.

We present a unique case of a 16-year-old male patient who was eventually diagnosed with a large enterolith arising from a Meckel's diverticulum. The enterolith had caused intermittent intestinal symptoms for three years before resulting in small bowel obstruction requiring surgical intervention. Meckel's enterolith ileus is very rare with only few cases described in the literature. To our knowledge, this is only the second case of Meckel's enterolith which had caused intermittent symptoms over a period of time, before resulting in ileus, and the first case where the intermittent symptoms lasted several years before bowel obstruction. The patient had been evaluated with colonoscopy, computerized tomography (CT), and magnetic resonance imaging enterography (MRIE); a calcified pelvic mass had been found, but no further diagnosis other than calcification was established. The patient presented at our emergency department, with symptoms of obstructive ileus and underwent exploratory laparotomy, where a large enterolith arising from a Meckel's diverticulum (MD) was identified, causing the obstruction. A successful partial enterectomy, enterolith removal, and primary end-to-end anastomosis took place; the patient was permanently relieved from his long-standing symptoms. Consequently, complications of Meckel's diverticulum and enterolithiasis have to be included in the differential diagnosis of abdominal complaints.


Introduction
Meckel's diverticulum is a common embryological remnant that can be found incidentally during surgery for other pathology, or may manifest as acute abdomen, most commonly due to diverticular in ammation. More rare complications of Meckel's diverticulum, including bleeding, herniation, intussusception, and enterolithiasis, have also been reported [1,2]. We present a rare case of a large enterolith formed inside a Meckel's diverticulum that was diagnosed in adolescence after having caused intermittent abdominal symptoms and nally small bowel obstruction.

Case Presentation
A 16-year-old patient presented to our outpatient clinic for evaluation of a pelvic calci ed mass, initially found three years earlier in an abdominal X-ray, during investigation of an episode of lower right quadrant pain (Figure 1).
At that time, the patient did not require any surgical intervention and was managed conservatively. He was advised to have an outpatient workup of this mass. He was evaluated by a gastroenterologist and underwent an MRI enterography and colonoscopy. e MRI enterography revealed a calci ed lesion in the distal ileum, located inside the pelvis, while the colonoscopy failed to recognize any lesion or in ammation in the terminal ileum. Meanwhile, the patient occasionally complained of nonspeci c abdominal symptoms, which did not prompt him to seek further medical attention and resolved automatically.
Two years later, we scheduled an abdomen computerized tomography (CT), as a follow up. Contrast-enhanced abdominal CT revealed the same calci ed lesion, 5 cm in diameter, that was in contact with the small bowel in the pelvis. e lesion had not grown in size during the last years. ree years after the rst onset of symptoms, the patient presented in our emergency department with symptoms of small bowel obstruction, namely, vomiting, intense colicky abdominal pain, and gas/ atus retention for 48 hours. Clinical examination revealed abdominal tenderness, distension, and hyperactive bowel sounds upon auscultation. Lab studies revealed mild leukocytosis. Plain X-ray showed multiple air-uid levels. A new CT scan of the abdomen revealed obstruction of the small intestine, by the aforementioned mass (Figure 2). e patient underwent an emergency laparotomy, where a loop of small bowel was found to be adherent to the pelvic wall. Upon dissection and mobilization of this loop from the pelvic wall, an enlarged and in ammed Meckel's diverticulum was identi ed. e diverticulum contained an enterolith, which was obstructing the bowel lumen. A partial enterectomy and an end-to-end anastomosis of the small bowel were performed. e operation led to resolution of the obstruction, and the postoperative course was uneventful. e pathology report con rmed the presence of a large enterolith, 5 cm in diameter, and ulcerative transmural inammation of the resected part of the small intestine. Six months following the operation, the patient was completely relieved from his occasional abdominal complaints and remained totally asymptomatic.
Informed consent was obtained from the patient for publication of this case report.
Meckel's diverticulum is complicated with enterolithiasis in 3-10% of cases [1]. In a large study by Park et al. involving 1476 patients with Meckel's diverticulum, it was found that 0.7% of asymptomatic patients and 6% of symptomatic patients had enterolithiasis at laparotomy [5].
To our knowledge, our case is only the second to describe a Meckel associated large enterolith that had been causing intermittent-type bowel symptoms for a certain period of time, before resulting in acute abdomen, due to obstructive ileus, thus requiring immediate surgical intervention [9]. Interestingly, this is the rst case that the intermittent symptoms had lasted for several years, without a de nite diagnosis regarding the cause of the symptoms being made in the meanwhile, before eventually producing small bowel obstruction.
In conclusion, enterolithiasis is an entity that can be a diagnostic challenge for the clinician. Meckel diverticulumassociated enterolithiasis can produce bowel obstruction. e clinician should include Meckel's diverticulum complications and enterolithiasis in the di erential diagnosis of abdominal symptoms, either acute or chronic.

Conclusions
Meckel diverticulum-associated enterolithiasis is a rare condition that can be either asymptomatic or produce nonspeci c symptoms but can also manifest itself as acute abdomen. Intestinal obstruction due to Meckel's enterolithiasis is very rare, with only few cases described in the literature. Our patient experienced intermittent symptoms for a course of several years before developing intestinal obstruction. Our case underlines that complications of Meckel's diverticulum and Meckel diverticulum-associated enterolithiasis need to be included in the di erential diagnosis of abdominal complaints, as this diagnosis can be particularly challenging.

Ethical Approval
Ethics approval was obtained from the Ethics Committee of Aretaieion University Hospital, Athens, Greece.

Consent
Signed written consent form was obtained from the patient.

Conflicts of Interest
All authors declare no con icts of interest.