Tulay Ozer md, Zonguldak Karaelmas Üniversitesi Tıp Fakültesi Hastanesi Radyoloji, Kozlu 67600, Zonguldak, Turkey. Email: email@example.com
Abstract Hydatid disease of the urogenital system, especially of the retroperitoneum and seminal vesicles, is a very rare condition. We report a case of hydatid disease located in the liver, retrovesical region and seminal vesicle that was diagnosed incidentally while investigating the etiology of syncope. Transabdominal and transrectal ultrasonography revealed hypoecoic multicystic masses which had thin septations and walls in the liver, retrovesical region and seminal vesicle. Abdominal computed tomography examination showed multicystic low attenuation masses in the same region. Pelvic magnetic resonance image findings revealed multiple cystic masses in the retrovesical region and the right seminal vesicle. In conclusion, the diagnosis of hydatid disease should be kept in mind with patients who have cystic lesions in seminal vesicle and retrovesical region.
Hydatidosis is a parasitic infection caused by Echinococcus granulosus. Although hydatid cysts are most frequently localized in the liver (73%) and lung (14%) by means of portal and systemic circulation, they may involve other tissues and organs.1 Hydatid disease localized in the urogenital system or retroperitoneum is rare and progression is slow, taking years.2 Hydatid disease of the seminal vesicles, either primary or secondary, is also very uncommon. Only five cases of hydatidosis of the seminal vesicles have been reported in the published literature to date.3–5
We report a case of hydatid disease which involves the liver, mesentery of cecum, transverse colon, retrovesical region and seminal vesicle in a patient who presented with syncope.
A 49-year-old man was admitted to the emergency department of the Karaelmas University School of Medicine, Zonguldak, Turkey, due to a recent history of syncope. The patient had same episode a year ago. His medical history was unremarkable. He was conscious and it was noticed that he was sweaty in the physical examination. His respiratory status was rapid and shallow. The arterial blood pressure and heart rate measured 60/40 mmHg and 125 beat/min, respectively. Routine laboratory investigation revealed a total white cell count of 9.5 × 103/µL (of which 6.5% were eosinophiles and 2.4% were basophiles) and an erythrocyte sedimentation rate of 18 mm/h. An indirect hemagglutination test was positive. Chest X-ray, cranial computed tomography (CT), carotid and vertebral artery color duplex Doppler ultrasonography (US), echocardiography and rhythm holter tests were normal.
Transabdominal US revealed hepatomegaly with two multicystic masses, one in the left lobe (55 × 31 mm) and the other in the right lobe (88 × 74 mm), which had thin septations and thin walls. Pelvic US showed a cystic mass in the retrovesical region and the right seminal vesicle. The cystic mass was further evaluated with transrectal US (TRUS), which indicated a slightly enlarged prostate gland (51 × 41 × 38 mm) and multiple cystic masses located in the right seminal vesicle. Abdominal CT examination revealed two cystic liver masses, similar to US findings (Fig. 1). Similarly, multiloculated cystic masses with multiple septations were also noted in the mesentery of the cecum and transverse colon. There was a multicystic (25 × 29 × 50 mm) low attenuation mass (15 HU) in the retrovesical region. The lesion was further evaluated with magnetic resonance imaging (MRI) on transverse, sagittal and coronal planes. The MRI findings revealed multiple cystic masses in the retrovesical region and the right seminal vesicle. T2-weighted sequences revealed hyperintense internal fluid with a hypointense wall and septations (Fig. 2). The cyst fluid was hypointense, similar to that of the urinary bladder and septations were isointense to the muscle on T1-weighted sequences.
An albendazole regimen was initiated three days before surgery and continued after surgery for two cycles to limit the implantation of any unrecognized spillage during surgery. Each cycle of the 15 mg/kg daily albendazole regimen for four weeks was interrupted by a 2 week drug-free period. The multicystic masses localized in the liver, mesentery of cecum and transverse colon were totally excised using the transperitoneal approach. In same surgical operation, the peritoneum was passed through extraperitoneally and then the multiple cystic masses localized in the retrovesical region and the right seminal vesicle were removed. No postoperative complications were observed. Histopathological examination of the surgical material revealed a typical hydatid disease with germinative membranes. At 1 year postoperatively, the patient was free of symptoms with no recurrence of the masses.
Hydatid disease is a helminthic infestation endemic in most sheep-raising countries in Asia, Europe, South America, New Zealand and Australia. The main form is due to Echinococcus granulosus. The life cycle of the tapeworm E. granulosus includes dogs or other canines as definitive hosts and variety of other vertebrates as intermediate hosts (e.g. sheep, cattle). Eggs, passed in feces, are ingested by intermediate host and develop into larvae which can be distributed throughout the animal's body. The resultant hydatid cysts infect the definitive when they are ingested, often through contact with infected dog or when contaminated water or vegetables are consumed.1
As the retroperitoneal cyst in the present case is not solitary, it should be accepted as a secondary hydatid cyst of the retrovesical and seminal vesicle. According to the classical theory of Deve,6 most cases of peritoneal hydatid cysts are secondary to the traumatic or spontaneous intraperitoneal rupture of primary hepatic, splenic or mesenteric hydatid cysts. The pouch of Douglas would then be the preferred site for the development of a secondary cyst in the pelvis, initially intraperitoneal and later subperitoneal.6
Retrovesical hydatid cysts primarily cause symptoms due to pressure on adjacent organs, such as the urinary bladder and rectum. Reported symptoms associated with the bladder include urinary frequency, urgency, retention and pain on micturation.7,8 In a recent review of the previously reported cases with seminal vesicle hydatidosis, symptomatology included dysuria, colic and hydatiduria,3 difficulty and a sense of burning during urination,4 frequency and acute urinary retention.5 Syncope is the presenting symptom of the currently presented case and there were no other complaints related to the genitourinary system.
The close proximity of the prostate, vas deferens, seminal vesicles and ejaculatory ducts are a diagnostic challenge to the masses located in that region. A retrovesical cyst mimics many processes, including rectosigmoid neoplasm, ovarian neoplasm, hydrosalpinx, tubarian pregnancy, cyst of the seminal vesicle, large ectopic ureterocele, posterior bladder diverticulum, urachal cyst and Mullerian remnant cyst.9 Radiodiagnostic techniques such as TRUS, CT and MRI are considerably helpful in making the diagnosis of pelvic hydatid disease. When the cyst is unilocular, a thick wall is generally present. Daughter vesicles initially cause a localized thickening of mother cyst wall. As they maturate gradually, new cysts form in the mother cyst, giving them a typical multiloculated appearance. The wall of the dead cysts usually calcifies. Infected cysts that appear like solid, space occupying lesions may confuse the diagnosis. Computed tomography findings of the hydatid cyst include a well-demarcated round low density (0–30 HU) mass with or without internal septations.1 Magnetic resonance imaging also provides valuable information for diagnosis and a clear evalution of cyst extension and tissue involvement.10
In conclusion, although retroperitoneal and seminal vesicle locations of a hydatid cyst are rare, hydatid disease should be considered when cystic masses in retrovesical and seminal vesicle are observed in a patient living in an endemic area.