Sonographic diagnosis of an ovary‐containing inguinal hernia with the formation of a corpus luteum in an adult female

Abstract

Ovary-containing inguinal hernia is a rare condition in women of reproductive age. It is occasionally found in young females, with sonography used to make the diagnosis1, 2. We report a case in which high-frequency ultrasonography was used to diagnose an inguinal hernia containing the left ovary in an adult female. A 28-year-old woman, who was otherwise healthy, presented with a palpable painless mass in her left groin. The mass had been present for 20 years but had recently dramatically increased in size. On physical examination a 5 × 3-cm non-reducible mass was noted in her left groin. Sonographic examination using a linear probe (7.5 MHz) showed a heterogeneous mass with multiple small sonolucent cysts (Figure 1), indicating that it was one of the ovaries. In addition, a hyperechoic portion of the mass surrounded by an arterial flow with a low resistance index of 0.45 (Figure 2) was observed on color Doppler ultrasonography, consistent with the presence of a corpus luteum. Further transabdominal sonographic scans (transvesical view) of the pelvis revealed the absence of the left ovary in the left lower pelvis, with a normal uterus and right ovary in their normal anatomic locations. It was concluded that the left ovary was located in the left inguinal canal, a diagnosis that was confirmed by surgical exploration. Gray-scale ultrasound image showing a heterogeneous mass—the left ovary—in the left inguinal region. The hyperechoic structure (arrows) is a corpus luteum. (a) Color Doppler ultrasound image demonstrating blood flow inside the ovary located in the inguinal hernia. (b) Pulsed wave Doppler ultrasound image showing a flow velocity waveform from the corpus luteum, with a low resistance index of 0.45. The presence of an inguinal hernia containing genital organs in females is usually due to an incomplete closure of the processus vaginalis of the peritoneum during embryogenesis2, when the processus vaginalis along with the round ligament of the uterus pass through the inguinal canal towards the labia majora. The contents of this type of hernia can include unilateral or bilateral ovaries, Fallopian tubes and even the uterus3, 4. There is evidence that the presence of this condition in female infants or teenagers might warrant subsequent surgical management. However, it is seldom reported in adult females. The morphological characteristics of the ovary in the hernia sac in our case, as assessed on sonographic examination, are exceptional because of the formation of a corpus luteum after ovulation according to the menstrual cycle of the patient, which provided ovarian functional information that could not be obtained in the young females described in previous reports. Clinically, different types of masses in the inguinal area have various characteristics5, 6. Therefore, the differential diagnosis of masses in the inguinal region is broad. Physical examination alone will not always provide a definitive diagnosis, and sonography can add valuable information to clinical diagnosis7, 8. In adult females cystic masses in the groin area are sometimes misdiagnosed owing to similarities in the morphological characteristics of the cystic portions of lesions. Mesothelial cyst of the round ligament, endometriosis and ovary-containing hernia are rare conditions in the inguinal area, and should be included in the differential diagnosis. Using color Doppler imaging in our case we detected vascular characteristics indicating herniation of the ovary, which can be differentiated from a round ligament cyst that shows minimal vascularity in the cyst wall or septa9. In addition, a history of groin pain during menstruation10 might be helpful in identifying inguinal endometriosis rather than herniated ovary or round ligament cyst. In summary, although ovary-containing inguinal hernia is seldom encountered by sonographers in adult females, in this case high-frequency color Doppler ultrasonography coupled with clinical information allowed a definitive diagnosis of this unusual condition. L. Yao*, Y. Mou*, H.-X. Wang*, * Department of Ultrasound, The First Affiliated Hospital, College of Medicine, Zhejiang University, #79, Qingchun Road, Hangzhou 310003, People's Republic of China