Case report and literature review: patient with gastroduodenal intussusception due to the gastrointestinal stromal tumor of the lesser curvature of the gastric body

Background Intussusception in adult patient is rare. Gastroduodenal intussusception due to the gastrointestinal stromal tumors is infrequently described in the literature. Authors present a case of gastroduodenal intussusception due to the low-risk gastrointestinal stromal tumor of the lesser curvature of the gastric body with literature review. Case presentation Sixty-two-year-old male was admitted to our hospital with symptoms of acute gastric outlet obstruction. Imaging studies confirmed a lesion of the gastric wall producing gastroduodenal intussusception with pylorus obstruction. Upon laparotomy a tumor mass of the lesser curvature of the gastric body that invaginated through the pylorus into the duodenum was found. Desinvagination and resection of the tumor with the adequate resection margins were performed. Histology reveled a low-risk gastrointestinal stromal tumor. Due to favorable outcome only observation was suggested by the multidisciplinary team. Conclusions Gastroduodenal intussusception due to the gastrointestinal stromal tumor of the gastric wall is a rare event. Surgical resection is the treatment of choice. In selected cases laparosopic resection of the tumor can be performed.


Background
Intussusception rarely occurs among the adult patients. It accounts for 5% of all intussusception cases and in only 1% causes intestinal obstruction [1]. Gastroduodenal intussusception is the most infrequent form of intussusception in adults, it occurs in less than 10% [2]. Clinical and radiological findings in a patient with gastric outlet obstruction, gastroduodenal intussusception and gastrointestinal stromal tumor (GIST) of the lesser curvature of the gastric body is presented.

Case presentation
62-year-old Caucasian male presented to the emergency room with acutely worsening epigastric pain lasting for several days and black stool lasting for a week. Symptoms of vomiting, inappetence and weight loss that have been lasting for the past six months without doctor appointment was also reported in medical history. Patient had a history of diabetes mellitus on insulin therapy. Upon clinical examination abdomen was not distended, there was no signs of guarding or rebound tenderness. Laboratory data showed anemia (hemoglobin 119 g/L, normal range 130-170 g/L; hematocrit 0.343, normal range 0.4-0.5), leukocytosis (13.5 10 9 /L, normal range 4.0-10.0) and normal value of C-reactive protein (below 5 mg/L, normal range 0-5 mg/L). Tumor markers CEA and Ca 19-9 were within normal range.
Due to melena lasting for a week, patient underwent esophagogastroduodenoscopy (EGD) and ultrasound of the abdomen on the outpatient bases only few days prior to admission to the hospital. EGD was technically demanding due to the poor passage of the endoscope through the stomach, duodenal bulbous and upper part of the duodenum. Inflation of the gastric body was not possible, therefore the visualization of the gastric wall was poor with no obvious intraluminal mass or hemorrhage detected. Additionally gastric peristalsis was described to be absent. Abdominal ultrasound showed tumor formation of the gastric body, measuring 7 × 5 cm, but no intussusception was described. CT scan revealed a 5.4 × 5.6 × 6.2 cm intraluminal tumor formation of the lesser curvature of the gastric body with well defined borders was described. Tumor mass caused invagination of the gastric cardia through the antrum and pylorus into the D2 part of the duodenum producing gastric outlet obstruction (Figs. 1,2). No dissemination to the parenchymal organs was described.
Explorative laparotomy was performed. Palpable gastric mass with impaction of the tumor through the pylorus into the duodenum without signs of disseminated disease in the abdomen. Was found (Figs. 3,4). Kocher mobilization of the duodenum and the head of pancreas was necessary for the successful desinvagination of the tumor. Anterior gastrotomy reveled a solid, well defined, intraluminal tumor of the lesser curvature of the gastric body just below the gastroesophageal junction. Circular radical resection of the tumor with one centimeter resection margin was performed. The gastric wall defect was sutured in transverse manner in two layers.
Postoperative period was uneventful and patient was discharged on the ninth postoperative day.
Sample was send for pathohistological examination. Macroscopically specimen contained a well-defined 7.5 × 5.5 × 4 cm solid, grey mass with no necrosis (Fig.  5). Microscopical examination with hematoxylin and eosin staining (HE) and imunohistochemical staining revealed GIST with expression of CD117 and DOG1 (Figs. 6, 7 and 8). Tumor invaded the submucosal layer and muscularis propria but no necrosis or lymphovascular   invasion was observed. Mitotic rate was 0/5/mm 2 . Proliferation marker Ki67 was less than 5%. Resection margins were free of disease. Tumor was pathologic staged as T3.
Patient case was presented on the multidisciplinary team meeting and due to low-risk GIST with favorable prognosis only observation is suggested.

Discussion and conclusions
Authors report a case report of 62 years old patient with gastric outlet obstruction due to the gastroduodenal intussusception caused by a large, low risk GIST of the lesser curvature of the gastric body.
In case of gastroduodenal intususception, reduction of the invagination can be performed endoscopically. In described case, where a large GIST led to the intussusception and protrusion of the gastroesophageal junction through the pylorus, endoscopic reduction of the invagination was not feasible. Moreover, upon endoscopy, the stomach was not visible and the tumor was not recognized. Both imaging techniques, ultrasound and CT scan of the abdomen, respectively, described tumor formation of the gastric wall with CT scan describing the gastroduodenal intusussception. Desinvagination and desimpaction of the tumor was not possible until Kocher mobilisation of the duodenum and pancreatic head was performed.
Surgery remains the treatment of choice for resectable GIST with no dissemination but also for oligometastatic disease with potentially resectable liver metastases. In many cases, especially in low-risk GIST, surgery represents the definitive treatment. A wide local resection with clear resection margins is recommended. In cases of invasion to the adjacent organs en-block resection should be performed. Systemic therapy may be indicated in patients with high-risk tumors and in patient with unresectable tumor or metastatic disease. Small lesions can be resected laparoscopically. Endoscopic resection of the GIST is not recommended [25]. In the literature only one case of endoscopic resection of the GIST producing intussusception was described. Endoscopic resection was performed in case of a 95-year-old patient who declined surgery. Tumor mesured 4 cm and was successfully reduced endoscopically. Due to the repeated invagination and surgery refusal only submucosal dissection of the lesion for the purpose of local treatment was performed [13]. Upon the literature review in cases of GIST producing gastroduodenal intussusception, lesions measured more than 5 cm (median 5.1 cm, mean 5.3 cm, range 2.5-8 cm) [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. As in described case, in majority of patients with large lesions, exploratory laparotomy was performed. The extent of resection ranged from wedge resection to subtotal gastrectomy [5-8, 10, 14-21]. In one third of described cases (29.5%), laparoscopic resection was performed ( Table 1).
GIST of the gastric wall rarely produces gastroduodenal intussusception. As shown in our case patients with low-grade GIST have favorable prognosis and in most cases radical surgical resection is the only treatment needed. When GIST arise from the gastric wall, resection of the tumor with adequate resection margins should be performed. For small lesions where desinvagination can be achieved endoscopically, laparoscopic resection of the tumor can be considered. In cases of large, impacted lesions, open approach with desinvagination and tumor resection is advisable.