Adult intussusception is an uncommon clinical entity encountered by surgeons. The exact mechanism is unknown, and it is believed that any lesion in the bowel wall or irritant within the lumen that alters normal peristaltic activity is able to initiate invagination. It is most commonly located at the junctions between freely moving segments and retroperitoneally or adhesionally fixed segments [
4].
About 90% of occurrences in adults have a well-defined pathological lead point, which may be a benign—such as benign neoplasms, inflammatory lesions, Meckel's diverticuli, appendix, and adhesions—or malignant lesion. In small intestine, malignant lesions (either primary or metastatic) account for 14–47% of cases, while malignant etiology is more prominent in large bowel representing up to 66% of the cases [
2].
Most adult patients with intussusception present with chronic and nonspecific symptoms suggestive of intestinal obstruction. Abdominal pain is the most common symptom followed by nausea, vomiting, and a palpable abdominal mass [
1,
2].
Preoperative imaging may help in identifying the causative lesion. Plain abdominal X-rays are typically the first diagnostic tool; with barium studies (showing “stacked coin” or “coiled spring” in upper GI series and “cup-shaped defect” in barium enema), ultrasonography (showing “target and doughnut sign” on transverse view and the “pseudokidney sign” in longitudinal view), and colonoscopy are also useful tools for evaluating intussusception [
5–
7].
In recent years, with a diagnostic accuracy of 58–100% in recent series, abdominal CT-scan (with the characteristic “
target sign”) has been reported to be the most useful tool for diagnosis of intestinal intussusception and is regarded superior to the above mentioned studies [
3,
8,
9].
Treatment of adult intussusception is always surgical. However, optimal management remains controversial. Most of the debate focuses on the issue of primary resection versus initial reduction followed by a more limited resection [
2,
9], keeping in mind that reduction should not be attempted with any degree of suspicion of malignancy, due to possible risks of intraluminal seeding, venous embolization in regions of ulcerated mucosa, and anastomotic complications, which may potentially lead to bowel perforation [
10]. Recently, there are several case reports about using laparoscopy as a minimally invasive technique for both diagnosis and treatment of adult intussusceptions.
Mesenchymal tumors constitute only 1% of primary GI cancers with GISTs being the most common. The annual incidence is between 7 and 20 cases per million per year [
11]. It occurs predominantly in middle-aged and older individuals and rarely in those under the age of 40. The majority of cases are sporadic; however, several familial cases with heritable mutations in the KIT gene have been identified [
12].
GISTs are thought to derive from neoplastic transformation of interstitial cells of Cajal (ICC). They may occur throughout the GI tract from the esophagus to the anus, but most commonly are found in the stomach (40–60%) and jejunum/ileum (25–30%) [
12]. Duodenum (5%), colorectum (5–15%), and esophagus (≤1%) are less common sites.
Sometimes GISTs are asymptomatic and are discovered incidentally during an endoscopy or on a CT done for another purpose. More often, they are associated with nonspecific symptoms (i.e., early satiety, bloating) unless complicated with ulceration and overt GI bleeding (40% of the cases) or grow large enough to cause pain, mass or a lead point of intussusception and intestinal obstruction (20% of the cases) [
12].
Contrast-enhanced CT is a preferred initial imaging study for screening and staging. However, other procedures such as ultrasound, endoscopy, intestinal capsule, and PET scan may also be used.
Surgical “en bloc” segmental resection with the goal of achieving negative resection margins is the treatment of choice for potentially resectable tumors, while initial therapy with imatinib may be preferred if a tumor is borderline resectable, or if resection would necessitate extensive organ disruption.
The prognosis of small intestine GISTs depends upon the adequacy of resection, tumor size, mitotic activity, and location within the small bowel, with small intestine having a worse prognosis than stomach [
13–
15].