Ileal Lipoma Causing Ileo-Ileal Intussusception: A Case Report

: Intussusceptions are rare entities among adult and adolescent populations. It is relatively common among children. Due to the lack of specific clinical features in adult and adolescent patients, its diagnosis is often delayed. Adult and adolescent intussusception could be due to many reasons


Introduction
Intussusception is rare in adults with an incidence of around 2-3 per 100,000 per year [1]. The incidence of intestinal lipomas ranges from 0.035-4.4% [2]. Lipomas occur anywhere in the gastrointestinal tract and a quarter of them occur in the small intestine [3]. Intestine lipomas arise from the submucosa in 90% of cases [3].
The greatest incidence of intussusception is between the ages of 3 months and 6 years. The older children (7-18year) account for 13% of intussusceptions and 23% occur in adults [4].
We report a case of intussusception due to lipoma arising from subserosal fat which is a very rare occurrence.

Case Report
A 17 years old boy presented to the surgical clinic with colicky central abdominal pain of one month duration, which was increasing in frequency. He had no vomiting or change of bowel habits or melena. On examination, he was comfortable and haemodynamically stable with a soft abdomen, and no palpable masses. Bowel sounds were normal at the time of examination. Ultrasonography was normal.
MRI abdomen showed ileo-ileal intussusception with a 29x12mm lipoma in the distal ileum acting as the leading A Case Report point (Figures 1 and 2). As there were no features of acute intestinal obstruction surgery was planned on the next available routine theatre list.  The patient underwent laparoscopy and the entire small bowel was examined from the DJ flexure up to ileocaecal valve to identify the intussusception which was noted in the distal ileum with dilated proximal bowel (Figures 3, 4, 5). This segment was exteriorized via a 5cm Pfannenstiel incision. The affected bowel segment was excised and end-end to hand-sewn bowel anastomosis was performed using 3/0 polyglactin interrupted seromuscular sutures.
Postoperative recovery was uneventful and the patient was discharged 3 days after surgery.
The patient was reviewed one month after discharge and was asymptomatic. He was safely discharged from follow-up.
In this case, the patient benefitted from minimally invasive surgery. Postoperative pain was minimal and early enteral feeding and mobilization were possible due to reduced surgical morbidity. There was a cosmetic benefit due to small incisions and an extraction port scar located below the bikini line.    The histopathology report confirmed a 25x15x15mm size intestinal lipoma with areas of infarction, necrosis and haemorrhage. Its stalk extended up to subserosal fatty tissue. There was no evidence of malignancy or dysplasia.

Discussion
Tumours of the small intestine account for 1-2% of all gastrointestinal tumours [5] and 30% of all small intestinal tumours are benign [6]. Gastrointestinal stromal tumours are the most common symptomatic benign tumours of the small bowel and lipomas are the second most common tumours [5].
Intussusception is an invagination of part of the intestine through the adjacent part [9]. Only 5% of all adult small intestinal obstructions are due to intussusception [10]. In 90% of adult intussusceptions, there is an organic cause and 60% are due to neoplasm. Of the small intestinal intussusceptions in adults, 24-40% are associated with malignancy [11].
The clinical presentation of adult intussusception is non-specific, making diagnosis very difficult [12,13]. Thus, a high index of clinical suspicion is a must and requires repeated clinical evaluation and radiological findings.
In both CT and MRI, lipomas are usually easy to diagnose on account of their density (-80 to -120HU). Intestinal lipomas are seen as well-circumscribed rounded homogenous lesions [5,14].
Preoperative diagnosis is important since the intra-op diagnosis is difficult and the wrong diagnosis can lead to unnecessary bowel resection [3].
Laparotomy is considered the choice of treatment for acute intussusception of adult patients due to the association with neoplasm [15]. But laparoscopic resection is the best approach because it is less invasive and associated psychosocial benefits are higher [3,5,12]. However, uncomplicated symptomatic lipomas can be safely excised by using endoscopic polypectomy [16,17].
This patient underwent an MRI scan resulting in pre-operative diagnosis of ileal lipoma. Thus, allowing laparoscopic evaluation and limited excision.
No malignant transformation of lipomas has been reported and therefore recurrence is unlikely [3]. Thus, follow-up is not needed.

Conclusion
Intussusception in adults is rare and mostly associated with an organic cause. Due to variation of symptoms, diagnosis can be difficult and pre-operative diagnosis is important to prevent unnecessary surgery and to identify malignant lesions. For intestinal lipoma, pre-operative diagnosis helps to perform a limited resection to preserve the length of the small intestine. For this benign condition, it is better to perform a minimally invasive procedure and the patient can be safely discharged from the follow-up.

Ethical Approval and Consent for Publication
Written informed consent was obtained from the father of the patient and the patient himself for publication of this case report and accompanying images.