Emerg Radiol DOI 10.1007/s10140-014-1248-7

CASE REPORT

CT and US findings of ovarian torsion within an incarcerated inguinal hernia Park Mee Hyun & Ah Young Jung & Yul Lee & Ik Yang & Dae Hyun Yang & Ji-Young Hwang

Received: 7 April 2014 / Accepted: 29 May 2014 # American Society of Emergency Radiology 2014

Abstract Inguinal hernia is relatively common in children. Although inguinal hernia is not frequently encountered in girls in comparison to boys, there are occasional cases of uterine or ovarian herniation in female indirect inguinal hernia. Incarcerated ovary in hernia sac has the risk of torsion and strangulation. We present an 8-year-old girl with painful mass in her left groin. With computed tomography (CT) and ultrasonography (US), we made the diagnosis of ovarian strangulation within an incarcerated inguinal hernia. Since ultrasound is primarily used for evaluation of groin mass, CT findings of an incarcerated inguinal hernia is rarely reported.

the inguinal canal. Normally, this undergoes obliteration soon after birth. If it remains completely patent, an indirect inguinal hernia is developed and partial proximal obliteration with a patent distal portion causes a cyst of the canal of Nuck in women. The diagnosis of torsion of herniated ovary should be made promptly before the necrosis of the ovary to protect this vital reproductive organ. We present an 8-year-old girl with an incarcerated ovarian inguinal hernia in which both computed tomography (CT) and ultrasound was performed.

Case report Keywords Inguinal hernia . Ovary . Torsion . Ultrasonography . Computed tomography

Introduction Inguinal hernia is relatively common in children with a range between 0.8 and 4.4 %, and it is more common in boys and infants [1]. Approximately 13.7–23 % of indirect inguinal hernia occurs in girls [2]. The incidence of ovarian content in female indirect inguinal hernia has been reported to be about 15–31 %, up to 82 % [2, 3]. Symptoms can be just painless, reducible mass at inguinal area, or edematous mass with significant redness and pain when incarcerated. The processus vaginalis is an embryonic developmental outpouching of the peritoneum that passes into P. M. Hyun : Y. Lee : I. Yang : D. H. Yang : J.
An 8-year-old girl visited our emergency unit with the complaint of palpable mass in the left groin with abdominal pain and vomiting. A small nodule in the left groin was first detected about 2 months ago, but it suddenly became larger and painful since the day before. On physical examination, a remarkable redness with a lump was palpated at the left inguinal region (Fig. 1), and her neutrophil count was slightly elevated by 8,520/μl. Clinically, inguinal lymphadenitis was suspected. Since the emergency ultrasound service was not available during the night hour, computed tomography of the abdomen and pelvis with contrast enhancement was performed. On CT, a heterogenous mass-like lesion was noted in the left inguinal area anterior to the left pectineus muscle (Fig. 2a). There were several internal low attenuating areas within the mass. Gray-scale and color Doppler ultrasonography was performed the next morning. The ultrasonography (US) revealed 4.9 cm×2.4 cm-sized oval mass that herniated through the inguinal canal. The mass was mostly solid with heterogenous echogenicity and multiple internal low-echoic cyst-like structures in the periphery (Fig. 3a). On color Doppler ultrasonography, there was no definite internal vascularity (Fig. 3b). Right ovary was normal in shape, position, and size. The diagnosis of ovarian inguinal

Emerg Radiol

Fig. 1 An 8-year-old girl visited emergeny unit due to a lump (arrow) with redness at the left inguinal region, abdominal pain, and fever

hernia and torsion or strangulation of the ovary was made. 3D coronal reformatted CT image of a mass was very similar to the ultrasound images demonstrating oval-shaped left inguinal mass with peripheral low attenuating small cysts (Fig. 2b). On surgery, necrotic and hemorrhagic ovary was identified within the indirect inguinal hernia sac (Fig. 4). The left adnexa including the ovary was found to be twisted 360° in the longitudinal axis. Left salpingo-oophorectomy was done.

Discussion Although inguinal hernia is not frequently encountered in girls in comparison to boys, there are occasional cases of uterine or ovarian herniation in female indirect inguinal hernia. The herniated ovary can be sliding or incarcerated, which means it cannot be reduced, at least not without very much external effort. Incarcerated ovary in hernia sac has the risk of torsion and strangulation. Pressure on the hernia content may compromise blood supply, especially veins, and often results in venous congestion and consequent ischemia, necrosis. However, the true risk to the blood supply of an incarcerated ovary lies not in compression but in torsion of the ovarian pedicle. Boley et al. [4] stated that the ovarian pedicle is narrowed and lengthened in state of incarceration and it increases the risk of torsion and infarction of ovary. Ultrasonography is widely accepted as a best modality for evaluation of abnormality of the inguinal area, especially in children, because it is free from hazard of radiation [5]. With ultrasonography, the nature of the mass and its relationship to adjacent structures can be well demonstrated. The ultrasonographic examination in our patient directly visualized

Fig. 2 a Axial contrast-enhanced CT image shows mass-like lesion in the left inguinal area (arrow). The mass did not show definite connection with intraabdominal organ and showed no significant enhancement. b On coronal reformatted image, the oval nature of the mass is clearly demonstrated with multiple ill-demarcated small low attenuating cystic lesions in periphery (arrows). Arrowhead indicates linea alba of abdominal wall

herniated structures entering the inguinal canal. Moreover, color Doppler ultrasonography can be simultaneously done to evaluate vascularity of the herniated structures. In general, CT should not be considered the first imaging modality in evaluation of the inguinal area in children due to the increased radiosensitivity. But when emergency US may not be available or other intraabdominal pathology is suspected, CT may be used instead of US such as in our case. In our patient, with the axial CT images alone, the diagnosis was not certain. But the coronal reformatted images demonstrating the oval shape

Emerg Radiol

Fig. 3 a Gray-scale longitudinal image at the left inguinal region shows enlarged heterogenous left ovary with edematous change and multiple peripheral cysts (arrow). b Color Doppler longitudinal image at the left inguinal region demonstrates no definite internal vascularity on left ovary

of the mass with the multiple small low attenuating lesions in the periphery helped confirm that the mass is actually an enlarged ovary. When evaluating inguinal mass in girls, possibility of genital organ herniation should be included in the

differential diagnosis, and as in our case, coronal reformatted CT images can give a clue when CT is done. The CT findings of the incarcerated ovary with torsion were similar to known common CT finding in ovary torsion such as asymmetric ovarian enlargement, multiple peripheral follicles, and decreased adnexal enhancement except for the inguinal location of the ovary [6]. The sonographic findings of ovarian torsion have been described in many literatures. The ovary demonstrates enlarged heterogenous mass-like lesion with multiple peripheral cysts and absence of Doppler flow [7]. However, the sensitivity of color Doppler ultrasonography is low because the ovary has a dual blood supply from the ovarian artery and uterine artery and arterial flow often persists long after loss of venous and lymphatic drainage [8]. Multiple cysts with varying size of 1 to 7 mm can be detected in inguinal ovarian hernias, but these are not real follicular cysts because they do not contain ovum [9]. The herniated ovary was larger than the usual ovary size of her age with heterogenous hyperechogenicity, probably due to hemorrhagic necrosis in our patient. Even though it is debatable whether the emergency surgery is essential for sliding ovary herniation or not, incarcerated hernia of the ovary increases the risk of ovary torsion. Prompt diagnosis with ultrasonography and early repair for the incarcerated inguinal hernia of the ovary may protect the ovarian tissue from the necrosis. In conclusion, although the diagnosis of strangulated ovarian hernia is mostly done using US, the knowledge of the CT findings especially coronal reformatted image, together with the suspicion of herniation of genital organs in girls, may be helpful in diagnosing this critical condition in an emergency situation when US is unavailable.

Conflict of interest The authors declare that they have no conflict of interest.

References

Fig. 4 In the operating room, the necrotic and hemorrhagic ovary was seen in the inguinal hernia sac

1. Huang CS, Luo CC, Chao HC, Chu SM, Yu YJ, Yen JB (2003) The presentation of asymptomatic palpable movable mass in female inguinal hernia. Eur J Pediatr 162:493–495 2. Choi KE, An SY, Kim KA, Ko SY, Lee YK, Shin SM, Han BH (2008) Characteristics and clinical course of ovarian hernias in infants. J Korean Soc Neonatol 15:80–83 3. Osifo OD, Ovueni ME (2009) Inguinal hernia in Nigerian female children: beware of ovary and fallopian tube as contents. Hernia 13(2):149–153 4. Boley SJ, Cahn D, Lauer L, Weinberg G, Kleinhaus S (1991) The irreducible ovary: a true emergency. J Pediatr Surg 26:1035–1038 5. Andrade K, Smith S, Goodarzian F (2014) An infant with an ectopic torsed testis in the abdominal wall. Emerg Radiol 21:223–225

Emerg Radiol 6. Lourenco AP, Swenson D, Tubbs RJ, Lazarus E (2014) Ovarian and tubal torsion: imaging findings on US, CT, and MRI. Emerg Radiol 21(2):179–187 7. DeJohn LM, Choudhary AK, Boal DK (2010) Acute ovarian torsion in an infant: diagnostic clues on supine and decubitus abdominal radiographs confirmed by ultrasound. Emerg Radiol 17(4):335–338

8. Oltmann SC, Fischer A, Barber R, Huang R, Hicks B, Garcia N (2009) Cannot exclude torsion—a 15-year review. J Pediatr Surg 44(6):1212– 1216 9. Goske MJ, Emmens RW, Rabinowitz R (1984) Inguinal ovaries in children demonstrated by high resolution real-time ultrasound. Radiology 151:635–636