Intestinal Lipoma as a Cause of Sigmoid Colo‐Colic Intussusception in an Adult: A Case Report

ABSTRACT

Adult intussusception is an uncommon and often unexpected diagnosis, typically driven by an underlying structural lesion. We report the case of a 43‐year‐old woman who presented with a month‐long constipation, five days of worsening intermittent abdominal pain associated with nausea, bilious vomiting, and anorexia. Contrast‐enhanced computed tomography (CECT) revealed a sigmoid colo‐colic intussusception caused by a 4 cm intraluminal fat‐density mass consistent with a lipoma. The patient underwent successful surgical reduction with segmental resection and primary anastomosis. Histopathology confirmed a submucosal lipoma of the sigmoid colon. This rare presentation highlighted the pivotal role of CT imaging in identifying adult intussusception and reinforces surgical resection as the optimal management strategy when a pathological lead point is present.

Key Clinical Message

This case highlights the rarity and clinical subtlety of intussusception in adults, a condition that often eludes early diagnosis due to its nonspecific presentation. Ultimately, this case reinforces the importance of early imaging and sound surgical judgment, ensuring favorable outcomes in an otherwise uncommon and challenging clinical entity.

1. Introduction

Intussusception is defined as the invagination of one segment of the gastrointestinal tract and its mesentery (intussusceptum) into the lumen of an adjacent distal segment (intussuscipiens). Intussusception is the most common cause of acute small bowel obstruction in children aged less than three years but comprises only 1%–5% of adult bowel obstruction presentations. Additionally, in the adult population, a pathological lead point is often identifiable, whereas a minority of pediatric intussusceptions present with a lead point. Of the 5% adult intussusception, malignancy forms the majority of lead point etiology (65%–70%) [1]. A lipoma is a rare cause of adult intussusception but has been documented in cases worldwide [2]. This report describes a case of a late presentation of an adult intussusception due to a lipoma with classical imaging findings and intraoperative photographs of the lesion. The role of bowel resection in patients with large submucosal lipomas should be considered to prevent future complications.

2. Case History/Examination

A 43 years old lady without significant past medical or surgical history presented to the emergency department with the history of intermittent abdominal pain for one month that had become more intense and persistent over the past five days. The patient also experienced nausea, three episodes of bilious vomiting, and loss of appetite since exacerbation. The patient was also constipated for over a month. However, there was no fever, weight loss, melena, and bloody diarrhea. Likewise, there was no family history of gastrointestinal malignancy.

At the time of the presentation, she was afebrile and her hemodynamics were stable. Upon examination, the patient was found to have a distended abdomen with normal bowel sounds i.e., 3 per minute. There was absence of tenderness, guarding and rigidity. Digital rectal examination (DRE) revealed empty and collapsed rectum.

3. Management

All the relevant laboratory test results were within the normal range i.e., white blood cell count of 8400/cu.mm (normal: 4000–11,000/cu.mm), hemoglobin of 13 g/dL (normal: 12–15 g/dL), serum sodium of 142 mEq/L (normal: 135–145 mEq/L), potassium of 4.1 mEq/L (normal: 3.5–5 mEq/L). Ultrasonography (USG) suggested intussusception with a classical target sign (Figure 1). This was followed by a CECT scan of the abdomen which revealed sigmoid colo‐colic intussusception with a length of 6 cm and a fat‐dense intraluminal lipoma of 4 cm acting as the lead point (Figure 2).

FIGURE 1.

Ultrasonography (USG) of abdomen and pelvis showing bowel loop with concentric alternating hyperechoic and hypoechoic rings, giving a target sign.

FIGURE 2.

A Computed Tomography (CT) scan of the abdomen revealing sigmoid colo‐colic intussusception due to colonic lipoma.

The patient underwent an emergency exploratory laparotomy. During surgery, telescoping of the sigmoid colon into the distal part was observed, with dilated proximal loops of the intestine. After reduction, a large (approximately 5 cm) and firm intraluminal mass was observed in the sigmoid colon. Palpable mesenteric lymph nodes were absent. Segmental resection of the sigmoid colon containing the mass (Figure 3) with an adequate margin of 3 cm was performed, followed by a hand‐sewn end‐to‐end colo‐colic anastomosis.

FIGURE 3.

A resected section of sigmoid colon with a pedunculated polyploidal growth (lead point) with ulceration measuring approximately 6 cm.

4. Conclusions and Results

The patient made a gradual but smooth recovery without any signs of sepsis during her post operative stay in the hospital. The patient's abdominal distension and projectile vomiting subsided. The bowel sounds returned on the 2nd post‐operative day and feeding was started thereafter. Similarly, independent ambulation, stool passage, and drain removal were done on the 3rd, 4th, and 5th post‐operative days respectively. The patient was finally discharged on the 6th post‐operative day.

Histopathological examination of the resected specimen revealed a pedunculated submucosal lipoma with ulceration. There was no evidence of malignancy or dysplasia. The patient had no complications during her follow‐up six month post‐operatively.

5. Discussion

Intussusception in adults is uncommon, representing about 5% of all intussusception cases and approximately 1%–5% of intestinal obstructions [1, 3, 4]. The exact mechanism of intussusception remains unknown. However, it is believed that any lesion or irritant within the bowel wall or lumen that disrupts the normal peristaltic movement, causes the bowel segment proximal to the stimulus to constrict and bowel segment distal to the stimulus to relax. This leads to telescoping of one segment of bowel into other [4]. The inducing factor promoting intussusception serves as the lead point [1]. Unlike intussusception in the pediatric cohort which is benign in most patients, adult intussusception is secondary to an underlying pathology in up to 90% [3]. Lead points are mostly malignant or benign mass or can be due to another primary bowel wall pathology such as Crohn's disease. Around 65% of cases are caused by malignant neoplasms (adenocarcinoma) [5]. Other reported etiologies include adhesions, lymphoid hyperplasia, cystic fibrosis, scleroderma, celiac disease, appendicitis, pancreatitis, and rectal foreign bodies [6]. Benign lesions account for only 30% of cases; responsible lesions include adenomatous polyp, lipoma, hemangioma, neurofibroma and leiomyoma [7]. Intestinal lipomas are rare and have a reported incidence of 0.035%–4.4%, making them a rare cause of adult intussusception, documented only in a few cases worldwide. It is more likely to be less than 1% in the colon and rectum. When present, they are most frequently located in the right hemi‐colon [8], which was contrary to our case i.e., sigmoid colon.

The size of lipomas reported in the literature varies from 2 mm to 30 cm. The small lipomas tend to remain asymptomatic and are usually detected incidentally. Larger lipomas are more frequently symptomatic, those more than 4 cm are considered giant and produce symptoms in 75% of cases and can mimic symptoms of colonic malignancy i.e., bleeding or obstruction while the main symptom reported is chronic, colicky abdominal pain [9]. In our case, the lead point was a giant pedunculated submucosal lipoma.

Adult intussusception has a non‐specific presentation and is often not considered in the differential diagnosis for abdominal complaints. The classical pediatric triad of abdominal pain, bloody diarrhea, and a tender abdominal mass is rarely seen in adults. Abdominal pain, nausea, altered bowel habit, and bleeding per rectum may be reported in adults or the patient may present with features of acute bowel obstruction [1]. Likewise, our patient had presented with constipation for weeks, that ultimately culminated into intestinal obstruction.

Colonoscopy may allow direct visualization of the lipoma, which can appear as a yellow, smooth mass with a pedunculated or sessile base. Characteristic endoscopic features include the ‘cushion sign’ (forcing the forceps against the lesion results in depression and then restoration of the mass) and ‘naked fat sign’ (fat extrusion during the biopsy) [10]. Smaller lipomas (less than 2 cm) may not require intervention if they are asymptomatic. Larger lipomas are more likely to be symptomatic and may require intervention. There is some evidence to suggest that endoscopic removal of larger lipomas (more than 2 cm) is associated with a greater risk of perforation [11]. Therefore, large symptomatic lipomas usually require surgical resection.

It is generally accepted that most cases of adult colonic intussusception will require surgical intervention, with en‐bloc resection without reduction of the affected segment due to the high risk of underlying malignancy. Reduction before limited resection may be appropriate for cases of small bowel intussusception where a pre‐operative diagnosis of benign etiology can be confirmed, as was done in our case [12]. Colonoscopy can usually distinguish colonic lipomas from cancer and other neoplasia, especially when the overlying mucosa is intact. However, it should be kept in mind that in a few cases, accurate preoperative diagnosis can be difficult [13].

Surgical treatment includes resection, colotomy with local excision, limited colon resection, segmental resection, hemicolectomy, or subtotal colectomy. The choice of any of the above‐mentioned surgical interventions mainly depends on the lipoma size, location, and the presence or absence of definite preoperative diagnosis or disease complications. The time and the type of the surgical intervention differ and depend on the site, cause, and degree of obstruction. Most surgeons agree that resection is necessary, particularly in colonic intussusceptions and in older patients, because of the possibility of a malignant tumor. Some authors have recommended a selective approach to resection, depending on the site of intussusception, which influences the type of pathology [14, 15]. Chang and colleagues recommended operative reduction for small bowel intussusceptions but not for colonic intussusceptions [16]. Gupta and colleagues reported resection in 70% of colonic intussusceptions [17]. During the last years, a few selected cases of successful laparoscopic resection under colonoscopic guidance of symptomatic colonic lipomas have also been reported [18, 19].

In our case, we proceeded with an emergency exploratory laparotomy and limited sigmoid colonic resection due to many factors: pre‐operative imaging features suggestive of the benign nature of the lead point, the large size of the lipoma, the location of the lead point i.e., sigmoid colon and also due to the constraints of lack of colonoscopy services at our center.

Author Contributions

Shankar Adhikari: conceptualization, data curation, resources, writing – original draft. Riyaz Shrestha: formal analysis, project administration, writing – original draft. Mohammad Adnan Adil: formal analysis, writing – review and editing.

Funding

The authors have nothing to report.

Ethics Statement

The authors have nothing to report.

Consent

Written informed consent was obtained from the patient to publish this report in accordance with the journal's patient consent policy.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.