Mucinous appendix intussusception: Case report

Abstract

Introduction and importance

Intussusception is an intestinal invagination of one bowel segment into another. It occurs mostly in children, but it can show in adults due to different etiologies. Appendiceal neoplasms are rare and can mimic an acute onset of appendicitis. Appendiceal mucinous neoplasm is one of the subtypes of appendiceal malignancies found in less than 1 % of appendectomies samples.

Case presentation

We present the case of a 32-year-old woman with abdominal pain in the right upper quadrant, whose computed tomography revealed an ileocolic intussusception and a low-density tubular image in the distal loop. She underwent diagnostic laparoscopy and laparoscopic right colectomy. Biopsy results confirmed a LAMN with acute appendicitis and intussusception.

Clinical discussion

Appendiceal intussusception (AI) is associated with the alteration of peristalsis, in addition to multiple inflammatory conditions and diseases such as parasites, foreign bodies, Crohn's disease, and lymphoid hyperplasia. The pathophysiology of AI is not fully established, but the main appendicular alteration that has been associated with it is the presence of a tumor. AI lead points are typically pathological in 90 % of cases, 65 % of which are neoplastic in nature. Right hemicolectomy should be performed for tumors involving the periappendicular area or in those larger than 2 cm in size. Follow-up and surveillance colonoscopy is suggested.

Conclusion

Intussusception is a rare diagnosis in adults. However, malignancy should be suspected if identified.

Highlights

• •Appendiceal neoplasms are rare and can mimic an acute onset of appendicitis.
• •Intussusception of the appendix secondary to mucinous adenocarcinoma is a very rare condition.
• •The main appendicular alteration associated with appendiceal intussusception is the presence of a mass at that level.

1. Introduction

Intussusception is the invagination of one segment of the bowel into an adjacent one, causing obstruction and ischemia [1], [2]. It can be classified according to the segment of the bowel compromised: 80 % are enteroenteric, meaning the invagination involves only the small bowel, 10 % are ileocolonic where the terminal ileum invaginates into the ascending colon, 7 % are colocolonic compromising the large bowel and 1 % are gastroenteric [1], [3]. Nevertheless, the localization does not affect the unspecific signs and symptoms which are abdominal pain, nausea, and sometimes bloody stool [1], [2]. The challenging diagnosis is made by clinical findings in 32 % of cases, while computed tomography (CT) scans can diagnose 78 % of the cases.

Although this disease affects mostly the pediatric population, 5 % of cases are shown in adults caused by benign or malignant intestinal lesions in over 70 % of the cases [2], [3]. The presence of lesions in the bowel disturbs the normal peristalsis, which promotes the invagination of the sick segment [1], [3]. Because of its etiology, intussusception must be one of the differential diagnoses in bowel obstruction cases [1], [2].

Appendiceal neoplasms are found in 0.2–0.3 % of histopathological samples from appendicectomies and appendiceal mucinous neoplasms (AMN) correspond to 0.4–1 % of gastrointestinal tumors [4], [5]. The identification of an AMN in early stages may be incidental due to their similarities with acute appendicitis' signs and symptoms; meanwhile in the most advanced stages, in addition to abdominal pain, we find abdominal distension due to the accumulation of mucin in the peritoneal cavity [5]. The treatment of local appendiceal mucinous neoplasms is based on resection of the tumor and hemicolectomy is considered depending on the degree of spread of the lesion and other factors such as the degree of cell differentiation, compromise of the base of the appendix, and lymph node metastasis [5], [6].

Therefore, after ethical and institutional approval, previous informed consent was obtained, following SCARE guidelines [7] in order to describe a case that informs the presentation and surgical management of an ileocolonic intussusception secondary to an incidental finding of low-grade appendiceal mucinous neoplasm.

2. Presentation of the case

Our paper presents a 32-year-old woman with no surgical history, who attended the service due to a 5-day clinical presentation of high-intensity colicky abdominal pain in the right upper quadrant, which started after eating a large copious meal. The patient had been managed the day before consulting our service with secnidazole, fenoverine, and liquid diet without any improvement.

Physical examination revealed a patient with asymmetry in abdominal distension and pain 10/10 on palpation. Laboratory studies showed a white blood count of 9.900 μ/L, neutrophiles: 68.1 %, lymphocytes: 23.3 %, hemoglobin: 14.2 mg/dL, hematocrit: 40.8 %, platelets: 246.000 μ/L with normal creatinine and B-hCG. Computed axial tomography of the abdomen and pelvis was performed and showed a distended transverse colon. In addition, the main finding was the presence of an ileocolic intussusception and a low-density tubular image in the distal area of the intussusceptum loop, which did not rule out the possibility of appendicular mucocele in this location (Figs. A and B). Considering the possibility of the presence of an appendiceal mucinous neoplasm, it was decided to proceed to exploratory laparoscopy with possible intestinal resection.

Figs. A and B.

Axial plane (A) and coronal plane (B). Computed tomography scan showing concentric rings suggestive of intussusception. Green arrow represents appendix inside the intestinal loop and red arrow represents the external part of the intestinal loop. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Diagnostic laparoscopy showed the presence of an ileocolonic intussusception with a severely thickened cecal appendix at its base, with intussusception of the ileum into the colon (Fig. C). Therefore, a laparoscopic right colectomy was performed. The cecum was freed from the ascending and right transverse colon with ligasure. After mobilizing and identifying the duodenum, the ileocolic trunk was identified and ligated using hemolocks and ligasure. Minilaparotomy was performed, distal ileum and right colon were exteriorized with the use of intestinal protector. The ileum and right colon were sectioned, the specimen was removed and sent for anatomopathological analysis (Fig. D). Enterotomy and colotomy were performed followed by the anastomosis, the common enterotomy was closed and the second plane was reinforced with PDS suture. The procedure was completed without any complications and with minimal bleeding.

Fig. C.

Intussusception of the ileum into the colon.

Fig. D.

Surgical specimen.

The anatomopathological analysis of the surgical specimen revealed the presence of a low-grade appendiceal mucinous neoplasm with acute appendicitis and intussusception, a neoplasm involving the lamina propria and effacing the submucosa without infiltrating the muscularis propria. There were no postoperative complications in the patient, with adequate pain and surgical wound management. The patient was discharged postoperative day 4.

3. Discussion

The overall incidence of intussusception in adults is approximately 2 to 3 cases per 1,000,000 in the general population annually [8], [9]. The highest occurrence rate is in the 30 to 50-year-old age range [9]. Our patient was a 32-year-old female with a malignant etiology for an ileocolic intussusception.

When the cecal appendix is involved as the main point of intussusception, the clinical presentation may mimic acute appendicitis [10]. However, there are situations in which patients may be asymptomatic or present symptoms compatible with intussusception such as abdominal pain and vomiting for several, diarrhea, constipation, or melena, similarly to our case [11].

The pathophysiology of AI is not fully established, but the main appendicular alteration that has been associated with it is the presence of a mass at that level. It is considered that this pathology presents alteration of peristalsis and, in addition to the association with multiple inflammatory conditions and diseases such as the presence of parasites, foreign bodies, Crohn's disease, lymphoid hyperplasia, endometriosis, mucocele, and neoplasia as in this case [10].

Abdominal CT has been considered the main diagnostic tool for an intussusception [8], [9], [10]. However, it is considered that in some cases distinguishing between the different anatomical features of the main mass is not easy due to poor discrimination of the edematous bowel wall [9]. Despite this, in our case the report of the abdominal CT concludes that there were findings compatible with ileocolic intussusception.

In adult patients, intussusception lead points are typically pathological in 90 % of cases, 65 % of which are neoplastic in nature [12]. Although there are no macroscopic features of the appendix that allow differentiation benign from malignant lesions, right hemicolectomy should be performed for tumors involving the periappendicular area or those larger than 2 cm in size [9], [10]; as was done in this case. However, there are cases in which making this decision intraoperatively is complex. Alternatively, an interval right hemicolectomy may be considered at a later stage if the histopathology results confirm malignancy [10].

Primary carcinomas of the appendix are divided into two types: adenocarcinoma and neuroendocrine tumor [10]. In turn, adenocarcinoma is divided into mucinous and non-mucinous. Subsequently, since 2010 the World Health Organization (WHO) classifies appendiceal mucinous neoplasms into three categories: mucinous adenoma, low-grade appendiceal mucinous neoplasm (LAMN), and appendiceal adenocarcinoma [13]. In this case, postoperatively, frozen section analysis was requested, which confirmed the presence of low-grade appendiceal mucinous neoplasia (LAMN) with acute appendicitis and intussusception. LAMN is a very rare pathology, accounting for only 0.1–0.3 % of histopathologic findings after an appendectomy [10]. LAMNs have an excellent prognosis because these tumors are restricted. However, an LAMN may develop malignant potential once the tumors penetrate the appendicular wall, thereby spreading in the peritoneal cavity with gelatinous deposits and contributing to pseudomyxoma peritonei (PMP) [9].

Overall, a laparoscopic right hemicolectomy was conducted initially on the suspicion of a high-risk malignancy of the colon causing the colic intussusception, and a LAMN was pathologically confirmed after the surgery. Follow-up and surveillance colonoscopy was suggested to the patient.

4. Conclusion

Intussusception of the appendix secondary to mucinous adenocarcinoma is a very rare condition, and even more so with a clinical presentation of acute appendicitis if we consider that most of the diagnoses of primary appendiceal tumors are incidental. This case presents a clear example of how complex the study of abdominal pain can be, in which diagnostic imaging tools facilitated decision-making based on the observation of parameters considered out of the normal range for the condition.

Consent

Written informed consent was obtained from the patient to publish this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

Ethical approval of the institutional committee was made previous publication.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author contribution

Ricardo E. Núñez-Rocha, MD: Participated in drafting the article and revising it critically for important intellectual content.

Daniel Gómez: Made substantial contributions to conception and design, acquisition of data, analysis, and interpretation of data.

Mario Mahecha: Made substantial contributions to conception and design, acquisition of data, analysis, and interpretation of data.

Carlos Ariza: Participated in drafting the article and revising it critically for important intellectual content.

Ana Giraldo: Participated in drafting the article and revising it critically for important intellectual content.

Gabriel Herrera: Participated in drafting the article and revising it critically for important intellectual content.

All authors have revised and approved the final version of the manuscript.

Guarantor

Ricardo Núñez.

Research registration number

None.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Declaration of competing interest

Authors do not declare any conflict of interest.