Introduction
Colonic lipoma was first described by Bauer in 1757 [1], it is the second more common begnin tumor after adenomatous polyps, it can be a lead point for intestinal invaginations, intussusception in adults are rare and constitutes less than 5% of all intussusceptions. 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. Although it is idiopathic in 90% of cases in childhood, a pathologic lesion can be found in adults in 70%-90% of cases [2]. In this report we are presenting a rare case of colorectal intussusception caused by lipoma.
Case Presentation
A 35 years old male patient presented to the emergency room, complaining of severe abdominal pain with abnormal bowel disorders; bleeding per rectum and constipation for 3 days. During clinical examination, a mass was palpated in the lower left quadrant. Full blood count and C-Reactive Protein (CRP) were normal.
A Computed Tomography (CT) revealed a colorectal intussusception caused by an ovoid heterogeneous lesion of 42x38mm situated in the sigmoid colon. The blood flow in the mucosa around seemed intact. lipoma or liposarcoma were suspected (Figure 1).
Figure 1: A: CT showing colorectal intussusception; B: CT showing the lipoma.
An emergency decision was taken up for surgery, exploration found colorectal intussusception, after reduction; intraluminal sigmoid pedunculated mass was the lead point of invagination. The surgical procedure consists of a carcinological segmental colectomy with stoma; the condition of the bowel was not optimal for primary anastomosis (Figures 2,3).
Figure 2: Intraoperative findings of reduced colon with the lipoma.
Figure 3: operative specimen of pedunculated lipoma of sigmoid colon.
Microscopic study showed an adipocyte-composed material with inflammatory and infarcted mucosa.
Patient was discharged 3 days later with no complications.
A secondary end to end anastomosis were performed 6 weeks later.
Discussion
Usually, the colonic lipomas are small and asymptomatic [3]. They are therefore detected incidentally. In about 25% of cases, however, there are clinical manifestations, including colonic intussusception. More women (57%) are affected than men (43%) [4].
The most common clinical manifestation of colonic intussusception due to colonic lipoma is abdominal pain, which is present in 83% of cases. Other commonly identified symptoms are changes in bowel habits, especially constipation (18%), rectorrhagia (16%) and vomiting (14%) [4].
The use of ultrasound would appear to be a quick and minimally invasive procedure, representing the first approach to imaging by an experienced and competent operator [5].
With a sensitivity of 71-87% and a specificity of up to 100% [6], Computed Tomography (CT) scans can detect intussusception as a lesion with the typical aspect known as the "target sign" or "donut sign" . In addition, in the presence of a lesion of sufficient size, CT can determine whether a lesion is composed of adipose tissue; if this is associated with an oval shape, the suspicion of a lipomatous lesion is high [7].
Colonoscopy gives direct views of the lesion and biopsies. there are signs that are pathognomonic of lipoma, the "pillow mark" and the "bare fat mark" [7,8].
In over 70% of patients, at least 2 instrumental examinations are needed before the diagnosis of intestinal intussusception caused by a lipoma is made [4].
Colonic lipoma is most commonly reported in the transverse colon (25%). The second most common location is the sigmoid colon and the cecum (20.2% each) [1].
Surgical resection is needed in cases of symptomatic lipomas such us intussusception or bowel obstruction [9].
If the benign nature of the lesion is certain, the preferred option is simple removal of the lipoma. The procedure can be performed both endoscopically and surgically [4].
Complete surgical resection is required when lipomas are complicated by bowel obstruction or intestinal obstruction; resection is recommended by many in case of intussusception of the colon, especially in elderly patients, because of the high possibility of malignant neoplasm [4,7].
Conclusion
Intussusception in adults is a very rare but challenging condition to diagnose in time. diagnosis of colonic lipoma is rather complex in the preoperative setting. High suspicion and adequate testing (abdominal ultrasound, CT scan and colonoscopy) can allow for a quick diagnosis. Currently, surgery is the most common treatment option for intussusception caused by a lipoma. Management generally requires formal resection of the involved bowel segment because of the highly suspected malignancy and consequent obstruction-related complications.