A Rare Case of Primary Tubo-Ovarian Hydatid Cyst, Approved Pathologically and Molecularly

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Introduction
Hydatid cyst is one of the most common diseases of zoonosis.The way to transmit the infection is to eat contaminated water and food with parasite eggs or contact with infected animal.In humans Echinococcus granulosusis is the most common cause of hydatid cyst disease which is a rare parasitic infection, primarily involving the liver and lungs in about 29-65% and 25-48% of cases, respectively and also cysts can form in the bones, spleen, heart, brain and kidney (1, 2).Some sporadic cases may develop the primary hydatid cyst disease in the tubo-ovarian and retroperitoneal space (3, 4).According to the latest results, the pooled prevalence of hydatid cyst in Iran was estimated at 5% [95% CI: 3-6%] (5).The disease may have an asymptomatic period of several years until the onset of some complications, such as rupture of the cyst, pressure on the surrounding tissues and so on.The involved organ and also the number and size of cysts lead to a variety of symptoms (6), which may result in high-risk situations and severe complications with high mortality rate could have consequences such as anaphylactic shock caused by cyst rupture during surgery (7).The ovary is a highly organized composite of germ cells (oocytes) and somatic cells whose interactions dictate formation of oocyte-containing follicles, development of both oocytes and somatic cells, ovulation, and formation of the corpus luteum and can have various diseases (8, 9).Here, we present a case with primary tubo-ovarian hydatid disease from a nonendemic region.

Case Presentation
In a case report study, a 45-years-old female, resident of a rural area of Southern Khorasan province of Iran, was admitted with a six-month dull abdominal pain following irregular menstruation and metrorrhagia Volume 8, March -April 2023 Journal of Obstetrics, Gynecology and Cancer Research over one year.She was engaged in farming and animal husbandry.She had five full-term pregnancies and used oral contraceptives.
A large pelvic mass, inseparable from uterus and adnexa, was palpated on physical examination.An abdominal ultrasound assessment revealed a pelvic multiloculated 130 mm mass, suggesting a left tuboovarian tumor.Other organs were healthy in the ultrasound report.Computed tomogram (CT) scan of the abdomen showed a 120 by 52 mm solid-cystic lesion in the left adnexa, which was hypo-to hyperdense with peripheral contrast enhancement (Figure .1).Preoperative routine laboratory tests and chest radiographs showed normal results.Also, all tumor markers were negative.The patient underwent laparotomy with left adnexectomy, peritoneal cytology, and biopsies.No ascites was noted at operation, and other abdominal and pelvic organs were normal.The left fallopian tube and ovary were found as a cystic mass and were resected with the appearance of a tubo-ovarian abscess (Figure .2).

Discussion
Ovarian hydatid cyst has been reported from different areas including Africa (Ethiopia and Tunisia) (10, 11), Western Asia (Saudi Arabia) (12), and Southern Asia (India) (13).There are several studies of the tubo-ovarian hydatid cyst in the average age range of 50 (range: 34-84) years in Iran (14-16).The majority of reported cases were bilateral tubo-ovarian hydatid cyst.There are sporadic reported cases of isolated hydatid cyst of the fallopian tube (17, 18).These rare reports represent a low incidence of primary tuboovarian hydatidosis, which may lead to the suggestion of hydatid cyst due to E. granulosus as the differential diagnosis of multicystic tubo-ovarian lesions among suspicious patients in endemic areas (19).This case is a pure primary hydatid infection of the ovary from Iran.The diagnosis was made after laparotomy for the evaluation of the cause of the symptoms.However, the most popular methods of diagnosis are ultrasound, CT scan, and MRI.Imaging methods are much more sensitive than immunological tests (15).A high frequency (7.5 MHz) transvaginal ultrasound has been suggested as a useful tool for the detection of tubo-ovarian hydatid cysts (10).
Moreover, CT and MRI methods are used in the diagnosis of these cysts.Chest x-ray imaging is a useful tool for the detection of associated pulmonary hydatid cyst (20).Hydatid cyst may be suspected by gynecologist, radiologist, and histopathologist when a septated cystic pelvic mass is found in these imaging methods (12).

Conclusion
Hydatid cyst disease is still considered a public health problem in Iran.Primary tubo-ovarian involvement is a rare disease with fortuitous discovery, and its non-specific clinical presentation leads to the difficulty of the diagnosis.However, the ultrasound method, particularly high-frequency vaginal sonography, is suggested the method of choice to make a precise diagnosis and total resection of the lesions is the treatment of choice of primary tubo-ovarian hydatid disease.Molecular methods are suggested to confirm pathological and radiographic diagnosis.

Figure 1 .
Figure 1.Involvement of left adnexa in CT scan imaging Figure 2. Macroscopic appearance of primary tuboovarian hydatid cyst