Retroperitoneal Caecum and Looped Retroperitoneal Appendix - A Rare Cadaveric Finding

Introduction

Caecum is the first part of large intestine which is located in the right iliac fossa. It starts as a blind pouch which is covered all around by the peritoneum. Caecum continues upwards as ascending colon. It receives terminal part of ileum on its postero- medial wall. Vermiform appendix (appendix) is attached to the caecum on the posteromedial wall 2 cm below the ileal attachment.^1,2 Base of the appendix is usually fixed, and the tip is directed in various directions. Position of the appendix is described based on the direction of the tip as paracolic, retrocecal, splenic, promonteric, pelvic or mid-inguinal.^1,2 Variations in the caecal position have been described earlier. It can be subhepatic, lumbar, midline or in the left iliac fossa. It can be explained as the malrotation of gut during its development.³ However, variations in the appendix is rarely observed. Acute inflammation of appendix is one of the common causes of acute abdomen. Since clinical presentation varies with the position of appendix, knowledge of any variation in the location or presentation of the concerned organ is important to the treating clinician.⁴ This article reports a rare cadaveric dissection finding of retroperitoneal caecum and a looped appendix which can be of significance to the surgeons operating in the region.

Case Presentation

During routine abdominal dissection of a 65-year-old formalin fixed male cadaver, it was observed that the terminal part of the ileum was ascending upwards from the pelvic cavity. Caecum and appendix were not visible in the right iliac fossa, until the terminal ileum was lifted (Figure 1). When traced distally, we found that ileum opened on the anterior surface of caecum. Caecum was not easily visible and it was plastered posteriorly to iliac fossa. It was retroperitoneal in the right iliac fossa. Even the appendix was retroperitoneal in nature and it was plastered to floor of the iliac fossa. Appendix was attached to the base of caecum. It was 8 cm in length and had a peculiar “U” shaped bend 3.5 cm from its base. The most convex part was fixed to pelvic brim by a fascial band. Tip was reaching the lower part of caecum (Figure 2).

Discussion

Acute appendicitis is one of the most common reasons requiring emergency surgical intervention in young adults. Knowledge of variations in the position of caecum and appendix will help the surgeons to locate it promptly during the surgery.^4,5 A study in 2016 which was conducted on patients who underwent appendectomy operation reported retrocecal appendix as the commonest (39.6%) and sub caecal (1.88%) as the least common type.⁴ Another study on 28 cadavers reported that ileum was opening on to the anteromedial wall of the caecum in three cadavers, whereas in remaining 25 cadavers, ileum was opening on the posteromedial wall of caecum.⁵ Horseshoe shaped appendix, a rare variation of the appendix has been reported. These studies found the presence of two stumps communicating appendix to the caecum during surgical intervention of atypically presented appendicitis.^6,7

During both open surgery or laparoscopic approach of appendicectomy, identification of caecum and appendix will be the first step. So, the knowledge of any variations in their position or relations will help the surgeons in their surgical venture.

Conclusion

We are reporting a retroperitoneal caecum and a retroperitoneal looped appendix which was anteriorly masked by the terminal part of the ileum. The bend of the appendix loop was also fixed to the pelvic brim which is not reported so far. Since appendicular variations are very rare, this knowledge can be of significance to the surgical trainees and the surgeons.

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Acknowledgement

The authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. Results from such research can potentially increase mankind's overall knowledge which can then improve patient care. Therefore, these donors and their families deserve our highest gratitude.