|Year : 2022 | Volume
| Issue : 2 | Page : 146-150
Coexisting Multiple and Complex Peritoneal Variations and Agenesis of Vermiform Appendix
Mehtap Tiryakioglu, Sevda Lafci Fahrioglu, Selda Onderoglu, Sezgin Ilgi
|Date of Submission||16-Sep-2020|
|Date of Acceptance||26-Jan-2022|
|Date of Web Publication||30-Jun-2022|
Source of Support: None, Conflict of Interest: None
We have come across a series of variations on our cadaver during routine dissection of the abdominal viscera. The amount and extent of the variations were unexpected in one cadaver, and they were followed one after another as listed: a peritoneal cyst formed by the parietal peritoneum that was stuck to the anterior surface of the right kidney, intraperitoneal duodenum, intraperitoneal ascending colon, partially constricted transverse colon, and several peritoneal strings running in between the various parts of the visceral peritoneum and the parietal peritoneum covering the abdominal wall, unusual location and size of the root of mesentery, and agenesis of the vermiform appendix. Our cadaver's medical history has not shown any surgery; it never showed any scars on the abdominal wall that might have indicated surgical operations. Peritoneal variations and agenesis of vermiform appendix are of great importance during diagnostic monitoring as well as surgical interventions. Extensive peritoneal variations in one patient may cause some extremely critical complications during the peritoneal dialysis, as well as during the laparoscopic approaches. We present these multiple and complex variations in one cadaver with respect to serious clinical complications that may come out because of ignorance of such cases.
Keywords: Agenesis of vermiform appendix, malformation, peritoneal cyst, peritoneal adhesion, peritoneal band, parietal peritoneum, peritoneum, renal peritoneal sac
|How to cite this article:|
Tiryakioglu M, Fahrioglu SL, Onderoglu S, Ilgi S. Coexisting Multiple and Complex Peritoneal Variations and Agenesis of Vermiform Appendix. J Anat Soc India 2022;71:146-50
|How to cite this URL:|
Tiryakioglu M, Fahrioglu SL, Onderoglu S, Ilgi S. Coexisting Multiple and Complex Peritoneal Variations and Agenesis of Vermiform Appendix. J Anat Soc India [serial online] 2022 [cited 2022 Sep 25];71:146-50. Available from: https://www.jasi.org.in/text.asp?2022/71/2/146/349531
| Introduction|| |
The peritoneum is a double-layered serous membrane and the most extensive and complex structure within the abdominal cavity. It consists of mesoderm-derived squamous epithelium. It covers the free surfaces of the intra-abdominal organs and the abdominal cavity. The parietal peritoneum covers the abdominal walls, whereas the visceral peritoneum envelops the intraperitoneal abdominal viscera.
Development of the peritoneum and the digestive tube cannot be considered separately; the viscera grow to invaginate the mesodermal peritoneum. Once organs start growing and pushing, they change their positions, the peritoneum relocates accordingly. Differences in development and rotation of the primitive bowel tube are the main cause of the deviations in the peritoneal structure in adults; thus, a brief look at the embryological development of the peritoneum would be explanatory.
The early gastrointestinal tract is in the form of a tube suspended between the anterior and posterior wall of the embryonic body cavity within two layers of mesoderm: the primary ventral and the primary dorsal mesenteries. As the gut tube starts rotating, the organs begin situating within the body cavity. The peritoneum also moves along; at the end of the midgut rotation, the parts of the peritoneum from one viscus to another and also between the abdominal wall and viscera are described differently. These anatomical terms include the peritoneal ligament, peritoneal fold, mesentery, and omentum. The mesentery is a double-layer visceral peritoneum suspending the intraperitoneal organs such as the small intestine and the transverse colon to the body wall, and the omentum is part of the visceral peritoneum connecting the stomach to the liver and transverse colon.,
The peritoneum stretched between porta hepatis, duodenum, and lesser curvature of the stomach is known as the lesser omentum. Greater omentum is the greatest fold of the peritoneum and formed by the peritoneum covering the anterior and posterior sides of stomach extending downward like an apron and turning back to form the transverse mesocolon. The peritoneal space located between the parietal and visceral layers of the peritoneum has two main portions as the greater and the lesser sacs that are connected by an epiploic foramen., Usually, the organs developed within the peritoneal layers remain intraperitoneal, while the organs developed connected to the abdominal wall remain retroperitoneal. Organs developed intraperitoneal during early stages of development, yet their dorsal mesenterium fused with the posterior abdominal wall is called secondary retroperitoneal organs. The ascending and descending colon, duodenum, and pancreas develop as secondary retroperitoneal organs.
| Case Report|| |
During routine abdominal dissection in the anatomy laboratory, we encountered a series of anatomical variations on a 72-year-old Caucasian male cadaver. His medical history did not show any significant disease or surgical information, and his body showed no scars on the abdominal wall.
The peritoneal cyst (sac) attached to the anterior surface of the right kidney was the first gross anatomical deviation observed during our dissection. The blind sac was full of peritoneal fluid about 150 cc and extending upward through the hepatorenal recess [Figure 1]a. It is formed by the parietal peritoneum of the right lumbar region by flapping over itself around the right kidney and sticking around its anterior surface and edges [Figure 1]b and [Supplementary Figure 1]. The upper end of the cyst was blended with the parietal peritoneum within the hepatorenal recess. The right kidney was not fixed to the posterior abdominal wall; instead, it was mobile and suspended by the peritoneal sac. The posterior aspect of the kidney had no adipose tissue when easily lifted [Supplementary Figure 2]; therefore, the fat tissue forming the renal bed was thought to be the perirenal fat that is stuck with the pararenal fat. The parietal peritoneum of the posterior abdominal wall was partially missing in the right lower part of the lumbar region, where it reminded the missing part was the part which flapped over and formed the sac in front of the right kidney [Figure 1]b, [Figure 2], and [Figure 3]. The border of the missing peritoneum on the left side was tracing the inferior vena cava on its anterior surface while the right side was passing in front of the right iliac muscle and transversus abdominis fascia.
|Figure 1: (a) Renal peritoneal sac formed by parietal peritoneum. (b) Removed right kidney with renal peritoneal sac (exposed)|
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|Figure 2: Missing part of parietal peritoneum after the removal of the right kidney|
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|Figure 3: Illustration of the renal peritoneal sac, root of the mesentery, intraperitoneal ascending colon, duodenum, and head of pancreas representing our case report|
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There was no vermiform appendix at the distal part of the cecum. It was palpated carefully to rule out the vermiform appendix intussusceptions within ileocecal and retrocecal areas, but could not be found. The cecum was much wider than ascending colon, and all three taeniae were observed at the distal part of the cecum without interruption [Figure 4].
Ascending colon was observed intraperitoneal within the same peritoneal layers with the cecum and transverse colon; it was running within the ascending mesocolon. It was difficult to distinguish the ascending colon from the transverse colon since a significant right colic flexure was not observed [Figure 5]a, [Figure 5]b, and [Figure 6].
|Figure 5: (a) Small intestines and ascending colon within the mesentery. (b) Intraperitoneal ascending colon (was placed on the anterior abdominal wall for demonstration purpose)|
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|Figure 6: Illustration of the obliterated part of the embryological mesentery and intraperitoneal ascending colon representing our case report|
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Transverse colon showed 12 cm long constriction at its distal end with extremely thickened wall; this part did not show any taenia or haustra and it was wrapped with a twisted mesocolon [Figure 7]; rest of transverse colon was not showing proper haustra or taenia coli, also and the lumen was wider than normal. There was another extreme constriction in its proximal part that seemed to be caused by a peritoneal band.
The duodenum and head of pancreas were intraperitoneal and the root of the mesentery (RM) observed as being tucked behind the head of pancreas [Figure 8]; RM was forming the inferior boundary of the epiploic foramen, and it was only about 5 cm long; therefore, there were no supra- and infra-mesenteric peritoneal recesses. The proximal part of the jejunum was suspended on the posterior abdominal wall through some peritoneal bands attaching the transverse mesocolon. Similarly, some other peritoneal bands were observed from the jejunal mesentery that had a clear attachment to the parietal peritoneum in front of the sacral promontory [Figure 9].
The left side of the abdominal cavity showed no deviation from the normal peritoneal and/or intestinal anatomy.
| Discussion|| |
Considering embryological development of peritoneum and intestines, our case is clearly showing extensive embryological variations on both dorsal and ventral mesenteries [Figure 6]. The parietal peritoneum appears to be separated from the posterior abdominal wall to form a peritoneal cyst in front of the right kidney and attached firmly to its edges and poles by leaving a wide peritoneal gap on the posterior abdominal wall in our case [Figure 1]a, [Figure 1]b and [Figure 3]. It is suggestive of a history of intra-abdominal surgery; however, there was no scar on the body, and his medical record showed no history of a surgery or a disease that might have caused it. The presence of the peritoneal mesothelial cysts could occur as a result of an inflammatory disease or a past intra-abdominal surgery. Our cadaver's history showed none of these implications, so we focused more on a congenital abnormality; however, an undiagnosed inflammatory disease should also be kept in mind for this particular case.
Agenesis of vermiform appendix is a very rare condition with a frequency of 1/100,000. It usually is encountered incidentally in cases of suspected appendicitis. The vermiform appendix, a narrow diverticulum develops from the distal end of the cecal bud during the descent of the colon. The anomalies of the vermiform appendix may be associated with other congenital anomalies such as jejunal atresia or short bowel syndrome. Collins examined 71,000 vermiform appendices and classified cecum and appendix anomalies in five classes: Type I showed absence of both cecum and vermiform appendix; in type II, cecum is rudimentary and there is no vermiform appendix; in type III, there is normally developed cecum with an absence of vermiform appendix; and in type IV, normal cecum accompanies the rudimentary vermiform appendix. Type V shows an enlarged cecum and absence of appendix vermiformis, showing great similarity to our case [Figure 4].
The intraperitoneal ascending colon is usually formed by a failure of the dorsal mesentery to fuse to the posterior abdominal wall and remain as intraperitoneal [Figure 3], [Figure 5]a, [Figure 5]b, and [Figure 6]. When an incomplete fusion occurs, the long mesentery causes abnormal bowel movements that can lead to volvulus. This may also lead to a retrocolic hernia, which is caused by a compression of the small bowel folding in the retrocecal pocket. There is neither retrocecal recess nor right paracolic gutter in our case as both cecum and ascending colon continues intraperitoneal.
The intraperitoneal duodenum and head of pancreas in our cadaver also remind a congenital anomaly showing the rotated midgut has failed to fuse with the abdominal wall and left the duodenum intraperitoneal. The RM was 5 cm long located behind head of the pancreas; thus, the right paracolic gutter, right infracolic, and left infracolic spaces were united. This situation can clinically cause very serious consequences when considered the abdominal interventions such as peritoneal dialysis; however, furthermore, there is an extensive gap on the parietal peritoneum on the body cavity in our cadaver [Figure 2] that can cause even more serious conditions in the abdominal organs.
Transverse colon had constricted part that was about 12 cm long at its distal 1/3rd [Figure 7]. The wall was thick enough to almost obstruct the lumen; taeniae and haustrae were interrupted. It reminded developmental intestinal stenosis that may occur from vascular accidents in the embryological period. Problems to expression of HOX genes and some receptors in the fibroblast growth factor family are held responsible as the reason for these vascular accidents during bowel differentiation. This is observed in 20% of intestinal atresia and stenosis cases. In our case, the part of the transverse colon before the constriction was wider than usual. Aganglionic megacolon or Hirschsprung disease is an intestinal disorder characterized by the failure of enteric ganglion cells to migrate completely during intestinal development; hence, the aganglionic segment of the colon fails to relax, causing intestinal stenosis as seen in our case. A rare type of the aganglionic colon named zonal segmental aganglionosis was first described by Tiffin et al. in 1940. In such cases, the presence of myenteric ganglionic cells can be detected proximal and distal to the aganglionic segment. Around 95% of the patients are diagnosed in early childhood; however, patients may remain undiagnosed until adulthood. To be accurate, our case needs to be examined histopathologically for the presence of aganglionic segment; however, a histopathological observation could not be done due to technical problems. The factors resulting in the intestinal obstructions can be several: adhesions from previous surgery, malrotation of midgut, tumors, hernias, inflammatory bowel disease, Crohn's disease, chronic constipation, volvulus, intussusception, etc., A volvulus is caused by a twisted colon and its mesentery and resulted with ischemia, yet the presented part of the transverse colon did not show any ischemia, although we observed twisted mesocolon which reminds a volvulus, particularly considering the transvers colon's increased volume caused its haustras to be disappeared [Figure 7].
Peritoneal bands or adhesions can cause compression within the abdominal cavity; they also are known as Ladd's bands and found because of failure of the embryonic mesentery to be obliterated properly, so the persistence of the parts of embryonic mesentery remains as the peritoneal bands. Depending on their route and extent, they may cause serious intra-abdominal problems such as intestinal obstructions, volvulus, extensive intra-abdominal pressure and pain, herniation, strangulation, constipation, diarrhea, etc. According to Nyakirugumi and Nduhiu, congenital peritoneal bands are the main reason for 3% of intestinal obstructions. When we consider the amount of the observed peritoneal bands in our case, there is a high probability of them, leading to a possible transverse colon volvulus.
| Conclusion|| |
Peritoneal and intestinal variations may not cause any clinical symptoms, so the prevalence of them may not be accurate. Peritonitis caused by perforation, ischemia, pancreatitis, and/or anastomotic leakage are some of the surgical emergencies affecting the entire peritoneal cavity. If the patient's peritoneal course and relationship to the organs show similar variation/s, as in our case, infection can easily spread, and the clinical symptoms may be worse than expected. Peritoneal structures such as ligaments, mesenteries, omenta, and peritoneal recesses can be a boundary for the infection spread depending on their location and conditional situations; however, our case express a great potential for the strangulations, volvulus, extensive peritonitis as there were some missing recesses due to the lack of proper root of mesentery and existence of many peritoneal bands. Furthermore, the missing parietal peritoneum on the right side was a great threat to the kidney and ureters. The several peritoneal strings and the abnormal peritoneal recesses around the intestines are surgically important as they may strangulate the bowel parts causing internal abdominal hernias. Although there are reports on individual variations such as intraperitoneal ascending colon, intestinal volvulus, peritoneal bands, and agenesis of vermiform appendix, there are no reports in the literature on the co-occurrence of them all in the same individual. We could not find any report such as a renal peritoneal sac in the literature. The overwhelming amount of the variations and our cadaver's age is controversial, yet this might be considered as an undiagnosed case that strongly emphasizes the importance of being aware of these variations as each one of them may cause serious complications during surgical interventions such as pancreaticoduodenectomy and distal/total pancreatectomy for an extensive tumor involvement throughout the entire pancreas/kidney or laparoscopic abdominal interventions. Atypical location of the RM may affect the way of cancer metastasis on related organs. Keeping the potential peritoneal variations in mind when going through an abdominal imaging process for any of the mentioned diseases and/or operations may prevent any possible misdiagnosis and/or mistreatment for such unfortunate case.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]