Clinical History
An 85-year-old woman with no pertinent surgical history was taken to the emergency department for an increasingly painful right inguinal mass, which was noticed approximately two weeks before. At clinical examination, the mass presented clear inflammatory signs, with oedema and erythema, and was painful at palpation.
Imaging Findings
An abdominal CT was performed (Fig. 1), albeit without intravenous administration of contrast media due to a history of prior allergic reaction, which disclosed a complex right inguinal mass with a thick wall, a partially fluid and fat content and infiltration of surrounding fat. The absence of contrast media limited the detailed analysis of its content, and it was not possible to determine if it contained any digestive structure or only an abscess.
The study was complemented with an ultrasound investigation (Figs 2 and 3), which disclosed a thick and hypervascular-walled, non-reducible fluid collection bearing internal echoes, suggesting a complicated inguinal hernia. Inside the hernial sac, a hypoechoic, multi-layered, blind-ended, non-compressible tubular structure was noted, measuring 7 mm in diameter, resembling a digestive structure.
This aspect suggested the presence of an inflamed appendix in the hernial sac, complicated by a periappendicular abscess, an entity known as Amyand’s hernia.
Discussion
Amyand’s hernia is defined as the presence of the appendix inside an incarcerated inguinal hernia, with or without appendicitis [1, 2]. It is a rare condition, noted in 0.2 – 1.7 % of hernias, and is more frequent in men. Female patients are usually postmenopausal, as in the presented case [3, 4]. It is more frequent in right inguinal hernias, due to the usual anatomical position of the appendix in the right lower abdominal quadrant [2].
Preoperative clinical diagnosis of Amyand’s hernia is difficult, because of its nonspecific presentation, similar to that of any incarcerated or strangulated hernia: pain and swelling of an irreducible right inguinal mass, possibly with a history of a known reducible inguinal hernia. Furthermore, as the diagnosis of an incarcerated inguinal hernia is often straightforward and an Amyand’s hernia is not suspected, imaging is not always performed resulting in delayed, often intra-operative, diagnosis [3, 4].
In terms of imaging investigation, ultrasound is usually the first modality used. The appendix may be seen inside the incarcerated hernia as a hypoechoic tubular structure with a layered wall suggesting a digestive structure, and can either have a normal size and appearance or show inflammatory signs such as oedema, hyperaemia and lack of compressibility. It is often surrounded by a fluid-filled cavity with a thick and inflamed wall suggesting a periappendicular abscess. Differentiation of the appendix from an incarcerated bowel loop is not straightforward, as it implies careful investigation of the entire length of a tubular digestive structure and confirmation of its blind-ended nature. If the appendix is perforated, this investigation is further complicated, as the appendix is not clearly visualised.
Reported complications of Amyand’s hernia include orchitis, epididymitis and gangrenous appendicitis, secondary to strangulation of the hernial sac. Intra-abdominal involvement with abscess is also reported [3].
Contrast-enhanced CT can be used to confirm the diagnosis and complications, and may also disclose an associated intra-abdominal complication such as intra-abdominal abscess or intestinal necrosis [2, 5].
Treatment of Amyand’s hernia is surgical [1], with removal of the necrotic and abscessed content, reduction of any viable hernial content and closure of the hernial orifice. Prognosis is generally good, with full resolution of symptoms postoperatively. It can however be poorer in cases where there is intra-abdominal involvement.
In the case presented, the patient underwent surgery, where the presence of a necrotic tubular digestive structure inside the abscessed hernial sac was confirmed and proven to be the appendix. The patient fully recovered without any complication.
Differential Diagnosis List
Amyand’s hernia.
Incarcerated inguinal hernia
with or without intestinal content
Strangulated inguinal hernia with bowel perforation
Diverticulitis in colon-containing inguinal hernia
Meckel’s diverticulitis in inguinal hernia
