Intussusception of the mucocele of the appendix: a case report in a conflict-affected region.

A 45-year-old woman presented with recurrent episodes of lower abdominal pain over the past two weeks, accompanied by decreased appetite and dysuria. She reported experiencing repeated episodes of abdominal pain over the last five years, with multiple visits to healthcare facilities, but no improvement. No past history of surgical operations. She is neither diabetic nor hypertensive nor asthmatic. Examination of the abdomen revealed mild tenderness in the right iliac fossa. USS abdomen showed a cystic lesion confined to the right iliac fossa with an ‘onion sign’, raising suspicion of a mucocele of the appendix, Fig. 1 . Patient information is shown in Table 1 . Fig. 1 Image 1 displays a cystic mass in the right iliac fossa (an onion sign), indicative of a mucocele of the appendix. Fig. 1 Table 1 Patient Information. Table 1 Patient information Findings Patient biodata 45-year-old female Clinical presentation Lower abdominal pain for two weeks, low appetite and dysuria Clinical examination Not pale, pulse 88BPM, BP = 130/80, tenderness in RIF CBC HB = 10 g/dl, TWBC = 5000 UG clear B. Urea 30 mg/dl S. creatinine 1.1 mg/dl HIV Negative HBV ag Positive HCV Negative USS abdomen Cystic right iliac fossa mass with onion sign suggesting mucocele of the appendix. Intervention Open appendicectomy Intraoperative findings and outcome Intusception of the mucocele of the appendix, the patient passed the early post-operative period without complications. Image 1 displays a cystic mass in the right iliac fossa (an onion sign), indicative of a mucocele of the appendix. Patient Information. An extended gridiron incision was performed, involving muscle cutting (Rutherford Morison incision). Intraoperative findings revealed a mucocele of the appendix measuring approximately 2 × 2 cm, which was intussuscepted into the cecum ( Fig. 2 ). There were no visibly enlarged lymph nodes, and no ascites was observed. A careful dissection was carried out to prevent mucous spillage. The tumour did not involve the base of the appendix. An appendicectomy was performed, and the specimen was sent for histopathological examination (see Fig. 3 ). Fig. 2 A mucocele of the appendix after being reduced from the cecum; the base of the appendix is free of the tumour. Fig. 2 Fig. 3 A specimen of the appendix mucocele. Fig. 3 A mucocele of the appendix after being reduced from the cecum; the base of the appendix is free of the tumour. A specimen of the appendix mucocele. The patient completed the postoperative period without complications and was discharged from the hospital after 72 h in good condition. Histopathology revealed a moderately differentiated Grade 2 mucinous adenocarcinoma, with no lymphatic or vascular invasion. A laparotomy was performed, and a right hemicolectomy was carried out; the specimen was sent for histopathology. The patient recovered well during the postoperative period with no significant complications.

Mohammed Hassan Ahmed: Writing the original draft, Conceptualisation, and editing of the manuscript. Eltahir Ahmed Eltahir: Writing, reviewing, and editing of the manuscript.

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

Informed consent was obtained from the patient for publications, including the images.

No,

Not applicable.

Eltahir Ahmed Eltahir, MD.

Intussusception of an appendiceal mucocele is a rare condition [ 1 ]. It is reported in 0.01 % of cases undergoing appendectomy. The main causes of intussusception of the appendix vary and include lymph node enlargement, polyps, or neoplasia [ 2 ]. It occurs more frequently in females than in males, with endometriosis being the most common cause. Symptoms vary widely, from asymptomatic to signs resembling appendicitis. Diagnosing it before surgery can be difficult [ 3 ]. Radiological investigations are extremely useful diagnostically, with CT scan sensitivity ranging from 60 % to 100 %. In LMIC, where a CT scan may not always be available, an ultrasound scan can offer a valuable preoperative diagnostic clue [ 3 , 4 ]. Here, we report a 45-year-old female diagnosed with intussusception of a mucocele of the appendix into the caecum, successfully treated with appendicectomy. This case report was prepared in accordance with the SCARE guideline for case reports [ 5 ].

Appendiceal mucocele-associated intussusception is extremely rare and often remains undiagnosed before surgery, especially in conflict zones where access to advanced diagnostic tools is limited. Abdominal ultrasound remains a valuable diagnostic method when access to CT scans is restricted. When performing an appendicectomy for an appendiceal mucocele, meticulous dissection is crucial to prevent the occurrence of pseudomyxoma peritonei.

Mucocele of the appendix, as a leading point to appendiceal intussusception, is a rare pathological entity with only a few cases reported in the literature [ 1 ]. To the best of the authors' knowledge, this is the second case report from the sub-Saharan region [ 4 ]. Symptoms vary, from asymptomatic to appendicitis-like symptoms [ 3 ]. In this case, symptoms included mild lower abdominal pain and lower urinary tract symptoms. An ultrasound showing a cystic mass with the onion-skin sign (a layered echogenic pattern) is a valuable radiological clue indicating a mucocele. Benjamin Caspi reported seven cases with cysts in the right iliac fossa and, in the presence of a normal ovary, concluded that a cystic lesion in the right iliac fossa without tubo-ovarian pathology strongly suggests an appendiceal mucocele [ 6 ]. Differential diagnoses include ovarian cyst, mesenteric cyst, tubo-ovarian abscess, and Crohn's disease with a mass effect. Although contrast-enhanced computed tomography (CT) of the abdomen remains the gold standard for diagnosing and characterising appendiceal mucocele [ 7 ], its use in this case was limited by resource constraints. The lack of CT imaging facilities in the patient's locality and financial barriers preventing transfer to a higher-level centre meant that cross-sectional imaging could not be performed (The health facilities in Sudan were severely affected by the war that started in 2023) [ 8 , 9 ]. As a result, the diagnosis relied on a combination of sonographic features, particularly the ‘onion skin’ sign, along with clinical presentation and laboratory tests. This highlights the importance of integrating accessible diagnostic tools in resource-limited settings, especially when managing rare surgical conditions. A preoperative diagnosis is crucial because intraoperative rupture may lead to a serious condition known as pseudomyxoma peritonei (PMP) [ 7 ]. The formation of pseudomyxoma peritonei (PMP) results from the rupture of an appendiceal mucocele. This condition can develop spontaneously or occur during surgery. The rupture causes mucus to spread within the peritoneal cavity. The occurrence of neoplastic mucoceles can involve serosal surfaces, thereby facilitating disease progression. It is widely believed that larger mucoceles (≥6 cm) pose the most significant risk of neoplastic potential and rupture. Evidence suggests that in low-grade appendiceal mucinous neoplasms (LAMNs), peritoneal spread is most associated with surfaces of exposed acellular mucin. The integrity of the appendix wall influences the advancing stage of the tumour (T4). This is the most critical factor, as it allows mucin to spill, leading to the development of PMP [ 10 ]. Management strategies for appendiceal mucocele intussusception vary and depend heavily on the individual case. Colonoscopy reduction might be an option in certain situations; however, this approach carries a significant risk of perforating the appendix and spreading mucinous fluid into the peritoneal cavity, which can cause pseudomyxoma peritonei. Surgical intervention is almost always necessary. Usually, an appendectomy suffices, especially when the base of the appendix remains unaffected. If the base is involved or malignancy is suspected, a more extensive resection, such as a right hemicolectomy, is needed to ensure oncological safety and minimise recurrence risk. In this case report, an extended gridiron incision was utilised. An appendectomy was performed since the base of the appendix and the caecum appeared normal. The intussusception was reduced entirely without breaching the caecum or the mucocele, and no enlarged lymph nodes or ascites were seen. The laparoscopic approach to appendiceal mucocele has been reported with varying results in the literature. While several case series and retrospective analyses have demonstrated the feasibility and safety of this procedure, mainly when meticulous surgical techniques and specimen retrieval protocols are employed, concerns remain regarding the risk of intraoperative rupture and the subsequent development of pseudomyxoma peritonei [ 11 ]. In this case, a right hemicolectomy was performed one month after the initial operation due to the histopathology results, which showed a moderately differentiated Grade 2 mucinous adenocarcinoma with no evidence of lymphatic or vascular invasion. Appendiceal mucinous adenocarcinoma treatment varies depending on tumour grade, disease spread, and the risk of peritoneal dissemination. For localised, non-invasive tumours within the appendix, an appendectomy may suffice. However, invasive adenocarcinoma, positive margins, or lymph node involvement usually require a right hemicolectomy with regional lymphadenectomy to ensure complete oncologic removal [ 12 ]. The main therapeutic challenge is preventing and managing pseudomyxoma peritonei (PMP). Once the tumour spreads to the peritoneal cavity, cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has become the standard treatment at specialised centres, offering improved survival rates compared to systemic chemotherapy alone [ 13 ]. For high-grade tumours or metastases outside the peritoneum, systemic chemotherapy such as oxaliplatin-based regimens, adapted from colorectal cancer protocols, is often used in adjuvant or palliative settings [ 14 ]. Perioperative care involves careful surgical handling to prevent tumour spillage, multidisciplinary case planning, and structured monitoring using imaging and tumour markers such as CEA and CA19–9 [ 15 ]. In resource-limited regions where advanced services are unavailable, utilising available diagnostic tools with the aim of early diagnosis is vital, and referral to specialised centres, if possible, is recommended. Case reports from LMIC are valuable for increasing awareness and improving outcomes.

As a single case report, this restricts the generalisability of the findings. Furthermore, limited access to CT scans and pathology services makes preoperative diagnosis considerably more difficult, highlighting the challenges faced in resource-constrained settings.

The authors declare no conflict of interest.