Amyand Hernia

What is the eponymous name of this anatomic finding? • Xray of the Week

Figure 1. What is the eponymous name of this anatomic finding?

Figure 2.

A. Coronal abdomen and pelvis CT.

B. Magnified view. Cecum (yellow arrows). Appendix in inguinal canal (red arrows)

Figure 3. Coronal MIP CT abdomen and pelvis in a different patient. Note the opacified appendix in the right inguinal canal. There is also a left inguinal hernia containing a short segment sigmoid colon without obstruction.

Discussion:

A vermiform appendix in an inguinal hernia, inflamed or not is known as Amyand hernia. (Figs. 1-3) It is a rare disease seen in about 1% of all hernias where complications such as appendicitis and perforated appendix within an inguinal hernia sac are even rarer, approximately 0.07-0.13% and 0.01% respectively [1-4]. The term was coined in honor of Claudius Amyand, a French surgeon, who performed the first successful appendectomy in 1735 on a 11 year old boy who presented with an inflamed appendix in the right inguinal hernial sac, perforated secondary to a metallic pin [1-3].

Amyand hernia is seen 3 times more commonly in children than in adults due to the patency of the processus vaginalis in the pediatric population [1]. In adults, Amyand hernia is exclusively on the right side and more common in males [1]. However, left-sided Amyand hernias may be seen associated with situs inversus, intestinal malrotation, mobile cecum or a large appendix. It can be accompanied by cecum, bladder, ovary, fallopian tube, omentum or a Meckel diverticulum [4]. It is usually an incidental finding during surgery; however, patients may present with sudden onset epigastric or periumbilical pain with localized tenderness in the right lower quadrant along with a tender irreducible mass in the inguinal or inguino-scrotal region. This clinical presentation is similar to strangulated inguinal or femoral hernia making clinical diagnosis of Amyand hernia difficult [1,3].

Although often an incidental finding at surgery, preoperative diagnosis can be confirmed with CT scan in patients with a clinical suspicion of appendicitis [1-4]. The CT findings in this patient shows a blind ended tubular structure arising from the cecum and extending into the inguinal sac (Figs. 1,2). Usually acute appendicitis is seen as dilated lumen, wall enhancement and thickening with periappendiceal fat stranding. However, in this case, the the appendix is normal. When scrotal involvement is suspected, sonography is a readily available and safe imaging modality[1, 2].

Table 1. Losanoff and Basson classification of Amyand hernias.

Treatment:

Losanoff and Basson proposed a classification scale to identify and treat Amyand hernias (Table 1) [5]. The literature recommends hernia reduction followed by no tension hernia repair. If appendectomy is performed then primary hernia repair without a prosthetic mesh is the best option to prevent infection. Use of synthetic mesh is avoided in the repair of contaminated abdominal defects because prosthetic material can increase the inflammatory response and result in wound infection. [1, 3].

References:

1. Ivanschuk G, Cesmebasi A, Sorenson EP, et al. Amyand's hernia: a review. Med Sci Monit, 2014. 20: p. 140-6 doi:10.12659/msm.889873 2. Green J and Gutwein LG. Amyand's hernia: a rare inguinal hernia. J Surg Case Rep, 2013. 2013(9) doi:10.1093/jscr/rjt043 3. Luchs JS, Halpern D, Katz DS. Amyand's Hernia: Prospective CT Diagnosis. Journal of Computer Assisted Tomography, 2000. 24(6): p. 884-886. doi:10.1097/00004728-200011000-00011 4. Morales-Cárdenas A, Ploneda-Valencia CP, Sainz-Escárrega VH, et al. Amyand hernia: Case report and review of the literature. Ann Med Surg (Lond), 2015. 4(2): p. 113-5 doi:10.1016/j.amsu.2015.03.007 5. Losanoff JE and Basson M. Amyand hernia: A classification to improve management. Hernia : the journal of hernias and abdominal wall surgery, 2008. 12: p. 325-6 doi:10.1007/s10029-008-0331-y

Shama Jaswal is an International Medical Graduate, currently doing research at Mallinckrodt Institute of Radiology (MIR), Saint Louis. She aims at pursuing Diagnostic Radiology residency and poses a keen interest in research alongside academics. At MIR, she has been fortunate to work on various oncology projects including the project in which they studied how the difference in fat metabolism in both sexes can affect the cancer survival and outcome, and how this study can further improve prognosis through treatment modification. Shama is both an accomplished sprinter and singer having won several national competitions in in each discipline in India. She also has a strong passion for cooking and gardening.

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Kevin M. Rice, MD is the president of Global Radiology CME

Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator.

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