INTUSSUSCEPTION CAUSED BY AN ADENOMYOMA OF THE ILEUM: A CASE REPORT.

Ahmed Elguazzar1, Amine Azami2, Mohamed Lahkim1, Ahmed Elkhader1, Rachid Elbarni1 And Abdessamad Achour1. 1. Department of general surgery, Avicenna Military Hospital, Marrakesh. 2. Department of pathology, Avicenna Military Hospital, Marrakesh. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 05 April 2019 Final Accepted: 07 May 2019 Published: June 2019 Copy Right, IJAR, 2019,. All rights reserved.

Open laparotomy was performed and showed non-reducible ileocecal invagination with necrosis of the intussusceptum and caecum ( fig.2) .Downstream, the colon was flat whereas upstream the small intestine was distended. There was satellite mesenteric lymphadenopathy.
Ileocecal resection was performed removing the ischemic segments, with immediate ileocolic anastomosis and abdominal drainage. The patient's postoperative course was uneventful. Subsequent control was satisfactory.
Surgical specimen was addressed for pathological examination. At gross examination, the submucosal tumour appeared well-defined, whitish and soft and solide. It measured 1.5x1.3 cm. The microscopic examination showing a tumor located in the submucosa and composed of glandular and tubular structures lined by regular columnar epithelium and surrounding by smooth muscle bundles(figure 3-a). Immunohistochemical examination revealed a strong expression of CK 7 (figure 3-b) and CK 19 (figure3-c) in the epithelial proliferation. The CK20 was negative in the proliferation and positive in the intestinal epithelium. The smooth muscle bundles are positive for the smooth muscle actin (figure3-d). These features were compatible with the diagnosis of adenomyoma of the ileum (Figure 3).

Discussion:-
Generally, adult represent approximately 5% of all intussusception cases and account for only 1-5% of obstructions in adults [3].
The clinical signs of intussusceptions including the classic triad associating paroxysmal abdominal pain, bloody diarrhea and palpable mass on examination, are found in children but are very rarely present in adults, estimated at 9.8% [5] . In fact, in adults, the presentation is most often non-specific with symptoms that can evolve in a chronic mode, including nausea, vomiting, constipation, slimming or simple abdominal distension [6].
The diagnosis of intussusceptions is based primarily on abdominal imaging which includes ultrasound or CT. The first examination is very widely used in children where its sensitivity and specificity are high. In adults, ultrasound can be limited by obesity or air distention and it is the abdominal computed tomography that seems to be most reliable examination to confirm the diagnosis, in particularly in pauci-symptomatic patients, with sensitivity ranging from 58% to 100 % [6; 7] , it allows to define the location, the nature and sometimes the etiology of Intussusception (showing a underlying tissue lesion) [7]. The two classic images are the "sandwich" image in longitudinal section drawing the head of the invagination and the "roundel" image in cross-section representing the intussusceptum. Almost 90% of adult intussusceptions are caused by a pathological condition that serves as a lead point such as carcinoma, polyps, colonic diverticulum, Meckel's diverticulum strictures, or benign neoplasm [6]. Malignancy is present in about 13-47% of enteric intussusceptions and in 33-62.5% of colonic intussusceptions [8][9][10]. it is for this high incidence of malignancy that surgical resection and without radiological decompression is recommended in most adult cases [11].
Our case reports acute intestinal intussusception of the adult secondary to adenomyoma which is a rare benign lesion of the gastrointestinal tact localized at the stomach, small intestine and biliary ducts [12]. Adenomyoma of the a d c b stomach is usually asymptomatic. Its occurrence in the small intestine is rare in children and extremely rare in adults. It was concluded that ileal adenomyoma often causes intussusception, especially in children, and a tendency towards the incidental discovery of intussusception was noted in adults, although it was not the same for our case. The preoperative diagnosis of intussusceptions is difficult, and the frequency of a correct preoperative diagnosis ranged from 40.7 to 50% in previous studies [5]. In our case, we were able to establish a preoperative diagnostic with CT.
The pathogenesis of adenomyoma has not been fully elucidated. Its histopathological findings are characterized by glandular structures lined by a cuboidal to tall columnar epithelium surrounded by bundles of smooth muscle cells; however, the histogenesis of the condition is disputed. The most widely accepted hypothesis is that these lesions represent a form of myoepithelial hamartoma or a type III pancreatic heterotopia [17,31]. In this study, immunohistochemical examination was performed in an attempt to increase our understanding of the pathogenesis of adenomyoma. As a result, we detected the expression of CK 7 and CA19-9 and the absence of CK 20 expression, which are similar to the characteristics of the pancreatic duct epithelium. Judging from these results and the absence of MUC 2 expression, it is suggested that the glandular component of our case was not composed of intestinal epithelial cells, but rather of pancreatic duct epithelial cells. Our case was diagnosed as adenomyoma of the ileum, therefore in our opinion the pathogenesis of this lesion supports the heterotopic pancreas theory.

Conclusion:-
Finally, we consider that adenomyoma of the ileum is a rare cause of intussusception in all age groups.It is also suggested that adenomyoma is a form of heterotopic pancreatic tissue. Our case is distinguished by the fact that it is rare to find an adenomyoma of the ileum complicated by intussusception with intestinal obstruction in the adult age group.