Introduction

Amyand’s hernia is defined as an inguinal herniation of a normal, perforated, or acutely inflamed appendix. This phenomenon was first described in an 11-year-old male by Claudius Amyand in 1735 [1]. Amyand’s hernia is a relatively rare presentation of appendicitis, with an incidence of less than 1% according to the literature [2–4]. Diagnosis can be difficult due to its rarity and nonspecific presentation, which may include a tender and nonreducible mass in the inguinal canal or scrotum. Preoperative diagnosis is very uncommon, and, often, Amyand’s hernia is confused with an incarcerated or strangulated inguinal hernia [3]. Although less than 2% of appendicitis occurs in children less than 2 years of age, most cases of Amyand’s hernia with appendicitis have been reported in premature neonates and infants, as well as postmenopausal women [5]. We report a case of Amyand’s hernia in a premature neonate who underwent a circumcision before presenting with signs of epididymo-orchitis. A more extensive workup and surgical exploration led to the discovery of an incarcerated and inflamed appendix present in a hernia sac.

Case

The patient was a 30-week premature 33-day-old male who presented to our service with swelling and erythema of the right hemiscrotum. The patient had a history of bilateral inguinal hernias and prior urinary tract infection. He had undergone a circumcision 1 day prior to this presentation. On examination, there was a reducible left inguinal hernia and a nonreducible right scrotal mass. Right-sided erythema was noted to be spreading to the inner thighs, perineum, and anterior abdominal wall. The patient was afebrile but in respiratory distress, requiring intubation. The white blood cell count was 10,300 with a left shift. Initial scrotal ultrasound demonstrated normal to increased Doppler flow to the right testicle and increased flow in the epididymis and in the inguinal canal (Fig. 1). A heterogeneous fluid collection was seen adjacent to the right testicle with an echogenic focus and significant soft tissue edema was seen along the scrotum (Fig. 2). The findings were thought to represent right epididymo-orchitis and associated abscess. Given differential concern for a bowel-containing hernia, a localized computed tomography (CT) scan was performed. The CT scan demonstrated gas within the fluid collection adjacent to the testicle, as well as a focus of gas within the inguinal canal (Fig. 3). No bowel obstruction was seen and the ileum and cecum had a normal appearance. The appendix was not definitely identified on the scan. The imaging findings were thought to represent epididymo-orchitis and gas-containing abscess. The differential diagnosis at the time also included an inflamed appendix within the hernia and, given the recent history of circumcision, Fournier’s gangrene was considered. The patient remained afebrile at this point, and his abdominal examination was otherwise unremarkable, except for lower abdominal erythema. Broad-spectrum antibiotics were administered and the erythema began to resolve. The patient remained afebrile. A repeat ultrasound 2 days later confirmed a focus of gas and a resolving epididymo-orchitis. Likely, in part due to the interval decrease in soft tissue edema, a hypervascular tubular structure extending from the cecum into the hernia sac was now evident (Fig. 4). The patient was continued on antibiotics for 10 days and was scheduled for a diagnostic laparoscopy with possible appendectomy and bilateral inguinal hernia repair.

Fig. 1
figure 1

Transverse sonogram of the scrotum with color Doppler demonstrates increased flow within the right testicle (small double arrows) and epididymis (small single arrow) as compared to the left (white arrowhead). Complex fluid is seen adjacent to the right testicle and scrotal edema is seen

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Fig. 2
figure 2

Transverse sonogram of the scrotum, demonstrating slightly superior to Fig. 1 a focus of echogenicity (arrow) in the right hemiscrotum with shadowing

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Fig. 3
figure 3

Coronal reconstruction of a contrast-enhanced (intravenous not oral) computed tomography (CT) scan through the inguinal region, showing two small foci of gas within the inguinal canal and right hemiscrotum (arrows). Fluid is seen within the right hemiscrotum. The right testicle is partially seen (black arrow)

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Fig. 4
figure 4

Top Longitudinal view of the inguinal region demonstrates a tubular structure extending into the inguinal canal (arrow). The structure is clearly communicating with the air-filled cecum (C) and has the typical ‘bowel signature’ on ultrasound, with an echogenic mucosa and hypoechoic bowel wall. Bottom Similar longitudinal view with Doppler demonstrates increased vascularity within the tubular structure, consistent with an inflamed appendix

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Upon entry to the peritoneal cavity, it became evident that the appendix was incarcerated in the right inguinal hernia sac. An uncomplicated laparoscopic appendectomy was performed, as well as bilateral inguinal hernia repairs. The patient tolerated the procedure well. His clinical course continued to improve, and he was ultimately discharged from the neonatal ICU on the 49th day of life.

Upon review of the pathologic data, the appendix was 5 cm in length and 0.4–0.6 cm in diameter. The serosal surface was grey-tan and smooth, with pinpoint areas of hemorrhage, but no gross defects. No fecaliths were identified on gross examination.

Discussion

Amyand’s hernia is found to be up to three times more common in children than in adults, secondary to a patent processus vaginalis. In neonates, acute appendicitis occurs in less than 0.1% of patients, and less than a quarter of these patients have their appendix incarcerated in a hernia sac [6]. The differential for a painful mass in the inguinal area may include incarcerated hernia, inguinal lymphadenitis, epididymo-orchitis, testicular torsion, and hydrocele. Pediatric patients may present with nonspecific symptoms such as irritability and lethargy, along with a tender mass near the inguinal canal. However, due to the low incidence of this phenomenon, along with similar laboratory findings, Amyand’s hernia is commonly mistaken for an incarcerated or strangulated inguinal hernia.

Making the correct diagnosis preoperatively requires awareness of this rare entity by the clinician, as well as physical examination findings consistent with a hernia mass without obstructive signs [7]. The appendix is most commonly found in the right hernia sac as a consequence of normal anatomical position, although left-sided Amyand’s hernia has been reported in the literature [8]. Explanations for a left-sided Amyand’s hernia include a mobile cecum, situs inversus, and intestinal malrotation. Ultrasound and CT scanning have been noted to be helpful in arriving at a preoperative diagnosis, although usually a nonspecific herniation is noticed with little else to suggest the presence of an appendix in the hernia sac [3]. More commonly, the patient is surgically explored with the intent to repair incarcerated bowel only to discover the appendix present in the sac.

Although the exact pathophysiology of this entity is unknown, it is theorized that the presence of a congenital band extending from the appendix into the scrotum through the inguinal canal ending at the right testis may play a role [9]. The association between Amyand’s hernia with appendicitis is also under debate. Some authors believe that appendicitis is an incidental finding with Amyand’s hernia. Others support the theory that the appendix becomes entrapped due to the contraction of abdominal muscles, leading to compromised blood flow with resultant inflammation and bacterial overgrowth [5, 6]. To our knowledge, there have been no reports of circumcision-associated inflammation of Amyand’s hernia. Although the relationship between the circumcision performed and the occurrence of appendicitis may be purely temporal, a proposed mechanism is that there was bacterial epididymo-orchitis as a result of the circumcision, with secondary inflammation of the trapped appendix in the hernia sac.

Treatment of this condition with concomitant appendicitis involves urgent surgical exploration of the involved area. Traditionally, Amyand’s hernia has been treated with open appendectomy and primary hernia repair. However, as in this case, laparoscopic surgery has become a more popular approach. This method allows increased visualization of the entire abdominal cavity, and is both diagnostic and therapeutic [2]. Other benefits of laparoscopy versus open Amyand’s repair include decreased postoperative pain and earlier discharge. The use of mesh for hernia repair is not suggested due to the contaminated abdominal wall and resultant risk of infection in the wound and appendiceal stump [10].

Conclusion

Amyand’s hernia represents a rare but important clinical entity. Proper management is dependant upon accurate recognition of the signs and symptoms of this condition. We present here a case of appendicitis of an Amyand’s hernia in the setting of associated epididymo-orchitis in a premature neonate.