Rectal lipoma as a lead point for colo-colonic intussusception.

Intussusception in adults is a rare condition and most of the time there is a pathologic lesion that serves as a leading point. Unless highly suspicious, intussusception causing chronic abdominal pain and obstructive symptoms are rarely diagnosed before the surgery. In this study, we report a colo-colonic intussusception in a 73-year-old man with an intraluminal rectal lipoma as the leading point.

Introduction

Intussusception in adults is rare and constitutes 5% of all intussusception in the Western world [1], [2]. Causes and symptoms of intussusception are different in adults and children. In contrast to the intussusception in children which presents acutely, in adults the symptoms might be acute, intermittent, or chronic, and thus the preoperative diagnosis is infrequent to be so easily established [3]. The symptoms in adults are most consistent with bowel obstruction instead of the classic triad of crampy abdominal pain, bloody stool, and a palpable mass [3]. Although it is idiopathic in 90% of cases in childhood, a pathologic lesion can be found in adults in 70%-90% of cases [4].

We report a colo-colonic intussusception in an adult whom an intraluminal rectal lipoma was diagnosed as a leading point.

Presentation of the case

A 73-year-old man was admitted to Emam-Hossein Hospital emergency department due to severe abdominal pain 2 days before admission. The pain was intermittent, diffuse, and progressive, and accompanied by diarrhea. There was no nausea. He denied mucus, melena, or fresh blood in the stool. The patient had no history of abdominal surgery or medical comorbidity. On physical examination, vital signs were normal. The abdomen was slightly distended with high-pitched peristaltic sound. His abdomen was soft but presented tenderness. There was no sign suggesting peritonitis. On digital rectal examination, the physician noticed a mass in the rectal canal. Laboratory tests were within normal range. Three plain abdominal views showed no signs of obstruction or perforation. Abdominal and pelvic computed tomography scan with intravenous and oral contrast demonstrated colo-colonic invagination of the rectosigmoid colon associated with a 4.5 cm × 3.5 cm intraluminal, heterogeneous fatty rectal mass approximately 4 cm far from the anus, likely as a lead point of intussusception (Fig. 1, Fig. 2, Fig. 3). Colonoscopy and proctoscopy revealed a submucosal mass compatible with lipoma filling the rectum without evidence of malignancy and necrosis. Barium enema reduction of colo-colonic intussusception was successful and the patient underwent transanal surgery after 3 weeks. Rectal lipoma was successfully managed by removal and enucleation. The resected specimen was a round soft yellowish-white capsulated mass. Histologic findings revealed the diagnosis of lipoma containing well-differentiated adipocytes. The patient made a satisfactory recovery and was discharged on the second postoperative day.

Fig. 1

Colo-colonic invagination of the rectosigmoid colon associated with a 4.5 cm × 3.5 cm intraluminal, heterogeneous fatty rectal mass.

Fig. 2

Colo-colonic invagination of the rectosigmoid colon associated with a 4.5 cm × 3.5 cm intraluminal, heterogeneous fatty rectal mass.

Fig. 3

Colo-colonic invagination of the rectosigmoid colon associated with a 4.5 cm × 3.5 cm intraluminal, heterogeneous fatty rectal mass.

Discussion

Intussusception occurs when a portion of the digestive tract becomes telescoped into the adjacent bowel segment. Those 2 segments are called intussusceptum and intussuscipiens, respectively.

This cause of obstruction has different etiology and management, depending on the age of the person involved. It is the most common abdominal emergency in childhood, second to appendicitis [5]. The peak incidence occurs between 5 and 9 months old and then decline [6]. An important difference between the intussusception in adults and children is the possibility of an underlying cause. This difference will bring about the difference in the management too. Adult cases are almost always treated surgically because of the large proportion of structural anomalies and the high incidence of malignancies [7] in contrast to the children that are treated with nonoperative reduction, unless there is evidence of bowel perforation, shock, or peritonitis [6].

This entity has been classified based on the location: entero-enteric, colo-colic, ileo-colic, and ileo-cecal [1]. The colo-colic can be subclassified into colo-rectal and recto-rectal [7]. The secondary intussusceptions in the small intestine are mostly because of benign lesions such as benign neoplasms, inflammatory lesions, and Meckel diverticula [4], [8], and conversely 60%-65% of large bowel cases have malignant underlying lesions [7]. Primary colon adenocarcinoma, lymphoma, and metastasis are the most common malignant causes of colonic intussusception [3].

Lipomas are benign fatty tumors that can be found in all parts of the gastrointestinal tract but are most common in the colon, with an incidence of 0.2%-4.4%. They are generally asymptomatic, but the giant ones (more than 4 cm) become symptomatic in 75% of patients. These giant ones are the most common benign tumors in the colon, which are responsible for intussusception [9]. In a review by Paškauskas et al., 46 cases were collected as cases of colonic intussusceptions due to colonic lipoma over the past 45 years and 37 of them were analyzed. They showed that the median age of patients was 48 years old and they mostly complained of abdominal pain ranging from mild intermittent colicky ones to severe abdominal cramps before intussusception and specific symptoms of intussusception after its occurrence. The most common location was right hemicolon, including the cecum (19%), ascending colon (38%), and transverse colon (22%). They also showed that the size of lipomas causing intussusception ranges from 4 to 16.0 cm [10].