Clinical diagnosis
Case 180
【Progress】
The following day, he underwent endoscopic surgery to attempt to resect incarcerated omentum. During the procedure, adhesive peritonitis was found and appendectomy was conducted.
【Discussion】
The anterior lower abdominal wall composes of three muscles; transverse muscle, internal oblique muscle and external oblique muscle. At the lowest abdominal wall, internal oblique muscle disappears and transverse muscle and external oblique muscle fuses, forming inguinal canal. Inguinal canal has deep inguinal ring and superficial inguinal ring. Namely, transverse fascia connecting with transverse muscle and external oblique aponeurosis connecting with external oblique muscle fuses and forms deep inguinal ring (1-3). Greater omentum, small bowel and/or large bowel can enter the deep inguinal ring, leading external inguinal hernia. Meanwhile, superficial inguinal canal is formed by external oblique aponeurosis, inducing to make a weak gap (1-3). Bowels and/or urinary bladder can enter the superficial inguinal canal through the weak gap, leading an internal inguinal hernia. Inferior epigastric vessels situate between inguinal external canal and inguinal internal canal which indicates a marker to differentiate external inguinal hernia from internal inguinal hernia on axial CT images (1-3). However, coronal CT images might be better for the differentiation because coronal images directly can visualize the external inguinal canal and the internal inguinal canal.
Greater omentum descends like curtain and covers most entire bowel. Greater omentum emerges from major curvature of the stomach, descends to the lowest portion of intraperitoneal space and ascends to the transverse colon. It functions a role of defense like an intraperitoneal police man. In short, if there happens to be appendicitis or gastric ulcer, greater omentum approaches and covers the lesion to prevent expanding of the lesion. Greater omentum has a number of milky spots which compose of monocytes, lymphocytes and neutorophils, filtering abdominal fluid (4). Then, greater omentum defend not only covering the inflame site but also battling the bacteria using leukocytes. However, these cells are considered to lack the recognition ability of malignancy (4). It is well-known that gastric cancer or ovarian cancer can proliferate aggressively in the greater omentum as called dissemination (5, 6).
In our case, CT showed greater omentum with fluids herniated into right external inguinal ring which was interpreted incarcerated greater omentum. Endoscopically exploration did not revealed the incarcerated greater omentum but fluid retention in the omentum, managing needle insertion and pulling out the fluid. Further, peritoneal adhesion with chronic appendicitis was found. Then, the management of appendectomy was conducted. It is unclear why appendicitis and external inguinal hernia of greater omentum with fluids happened simultaneously. We guess that greater omentum descended to cover the inflamed appendicitis and the swollen omentum entered the deep inguinal canal and lost the fluid-filtering ability by compression, leading the fluid retention.
【Summary】
We present a seventy six-year-old male presented in our hospital for persistent lower abdominal pain and swollen right inguinal canal. Endoscopically surgery revealed chronic appendicitis with inguinal hernia by greater omentum with fluid retention. It is in borne in mind that inguinal canal initiate from deep inguinal ring formed by transversal fascia and external oblique aponeurosis to superficial inguinal ring formed by external oblique aponeurosis. External inguinal hernia and internal inguinal hernia enter the deep inguinal ring and the superficial inguinal ring, respectively. Greater omentum has a number of milky spots which compose of monocytes, lymphocytes and neutorophils. It functions filtering abdominal fluid and cover the inflame lesion such as gastric perforation or appendicitis. In our case, he had chronic appendicitis and inguinal hernia of greater omentum with fluid retention. It might be that first, the greater omentum descends and covers the appendicitis and then inflamed greater omentum herniated to the external canal ring accompanied fluid retention due to lack of fluid-filtering ability by compression.
【References】
1.Fitzgibbons RJ, et al. "Clinical practice. Groin hernias in adults". The New England Journal of Medicine. 2015; 372 (8): 756–63.
2.Burcharth J, et al. The inheritance of groin hernia: a systematic review. Hernia. 2013; 17 (2): 183–9.
3.Simons MP, et al. European Hernia Society guidelines on the treatment of inguinal hernia in adult patients.. Hernia. 2009; 13 (4): 343–403
4.Selene Meza-Perez, et al. Immunological functions of the omentum. Trends Immunol. 2017 Jul; 38(7): 526–536.
5.Rangel-Moreno J, et al. Omental milky spots develop in the absence of lymphoid tissue-inducer cells and support B and T cell responses to peritoneal antigens. Immunity. 2009;30(5):731–43.]
6.Koppe MJ, et al. Recent insights into the pathophysiology of omental metastases. J Surg Oncol. 2014;110(6):670–5.
2020.2.5