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Abstract We present a rare case of a hydatid cyst involving the seminal vesicle of a 48-year-old man. Urinary retention was the initial symptom. Both imaging and clinical evaluation revealed a substantial retrovesical cystic mass. The histopathological report was ‘hydatid cyst of the seminal vesicle’.
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- Case report
A 48-year-old man visited our department presenting acute urinary retention. All the laboratory tests were normal, but the ultrasound showed hydronephrosis of both kidneys and the presence of a substantial (12.5 cm × 7.5 cm) retrovesical cystic mass.
A subsequent computed tomography (CT) scan showed a multichambered cystic lesion of over 11 cm filling the pouch of Douglas and displacing the bladder forwards and upwards, while remaining separate (Fig. 1).
Figure 1. Computed tomography scan showing a multichambered cystic lesion of over 11 cm filling the pouch of Douglas.
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The differential diagnosis was between an Echinococcus cyst of the pouch of Douglas and a cystic lesion arising from the minor pelvis, that is, cyst adenoma of the seminal vesicle.
A magnetic resonance imaging (MRI) scan followed without shedding any more light on the problem (Fig. 2). Surgery was deemed necessary, and using a retrovesical approach, the mass was removed intact avoiding any spreading of the parasite. The seminal vesicle was completely degenerated and was also removed. The macroscopic image of the cyst showed colorless, opalescent fluid and daughter cysts, typical of a hydatid cyst. There were no postoperative complications, and the patient was discharged on the eighth postoperative day.
Today, 2 years later, the patient has not suffered any local or systematic recurrence.
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Based on Medline, there are only eight other similar cases reported1–4 (Table 1).
Table 1. Case reports of hydatid cyst of the seminal vesicle
|Emir L., Karabulut A., Balci U., Gerimyanoglu C., Erol D. An unusual cause of urinary retention: a primary retrovesical echinococcal cyst. Urology. 2000 November 1; 56(5): 85|
|A 32-year-old man with an 11 cm × 10 cm × 9 cm retrovesical echinococcal cyst treated with surgical removal and administration of albendazole.|
|Sagglam M., Tasar M., Bulakbasi N., Tayfun C., Somuncu I. TRUS, CT and MRI findings of hydatid disease of seminal vesicles. Eur Radiol. 1998; 8(6); 933–5 A 64-year-old male with a 5.2 cm × 5.6 cm × 7.2 cm hydatid cyst of the left seminal vesicle which was excised totally.|
|Whyman MR., Morris DL. Retrovesical hydatid causing hemospermia. Br J Urol. 1991 Jul; 68(1): 100–1 A 68-year-old man with a 5 cm × 4 cm × 3 cm pelvic hydatid cyst surgically removed.|
|Pasaoglu E, Damgaci L, Tokoglu F, Boyacigil S, Yuksel E. Hydatid cysts of the kidney, seminal vesicle and gluteus muscle. Australas Radiol. 1997 Aug; 41(3); 279–9 A 58-year-old man with multiple hydatid cysts of the kidney, seminal vesicle and gluteus muscle treated with both surgery and medication.|
|Kuyumcuoglu U, Erol D, Germiyanoglu C, Baltaci L. Hydatid cyst of the seminal vesicle. Int Urol Nephrol. 1991; 23(5); 479–83 A 51-year-old man with a 6 cm × 4 cm × 5.5 cm hydatid cyst of the seminal vesicle which was removed surgically.|
|Pascual Piedrola JI, Huadle Alfaro A, Ipiens Aznar A. Retrovesical hydatid cyst communicating with spermatic ducts. Actas Urol Esp. 1983 Mar–Apr; 7(2): 151–4 A 48-year-old male with a 7.5 cm × 4 cm × 3 cm retrovesical hydatid cyst which was surgically excised|
|Deklotz RJ. Echinococcal cyst involving the prostate and seminal vesicles: a case report. J Urol. 1976 Jan; 115(1): 116–7 A 37-year-old man with a 10 cm × 10 cm retroperitoneal hydatid cyst underwent abdominal exploration and injection of 30 mL of 2% formalin solution in the cyst.|
|Polianichko MF, Rasskazov GK. Echinococcosis of the seminal vesicles simulating retroperitoneal sarcoma. Khirurgia (Mosk). 1971 August; 47(8): 120 A 69-year-old man with a 6 cm × 4 cm × 4 cm hydatid cyst of the seminal vesicle treated surgically.|
|Papathanasiou A., Voulgaris S., Salpiggidis G., Charalambous S., Fatles G., Rombis V. Hydatid cyst of the seminal vesicle. A case report and a review of the bibliography. A 48-year-old male with a 12.5 cm × 7.5 cm hydatid cyst of the left seminal vesicle which was removed surgically.|
The differential diagnosis was difficult and included all cystic (benign and malignant) lesions of the minor pelvis.5 The CT scan lead to the idea that this cystic mass could be oriented from the seminal vesicle.6 Masses of the seminal vesicles are not usually malignant. The most frequent tumors of the seminal vesicles are simple cysts, adenoma, cyst adenoma and leiomyoma. Seminal vesicle cysts can be acquired or congenital, and are believed to develop due to obstruction of the seminal ducts. They can be accompanied by other disorders of the urinary tract such as kidney agenesis, multi cystic disease, subfertility, hemospermia and infections. However, the large size of this specific cyst made the diagnosis of a simple cyst unlikely. Other possible tumors could be cysteosarcoma and finally hydatid cyst.
The speculation of a possible hydatid cyst of the seminal cyst is based in several factors. The medical history of the patient is very important. Our patient worked for several years in a slaughterhouse, being in contact with possible intermediate hosts of the parasite and also reported an Echinococcus cyst of the liver that had been surgically removed 5 years before. Useful laboratory tests include an increase in eosinophils in 33% of cases which rise dramatically if cyst leaks. But the serologic test of choice is enzyme immunoassay (EIA).7 Indirect hemagglutination is less sensitive and specific. It was negative in our patient. Ultrasound may give useful information. In our case, it indicated the presence of a substantial (12.5 cm × 7.5 cm) retrovesical cystic mass. A CT scan is also very helpful. It helped us to suspect a hydatid cyst by showing a multichambered cystic lesion with the characteristics of Echinococcus daughter cysts measuring 6.3 cm.
The mass was removed surgically. The different approaches to surgical removal of tumors of the seminal vesicles are perineal, intravesical or retrovesical. In this case, the first two were excluded mainly to avoid accidental perforation of the cyst and subsequent spreading of the parasite. Generally, the retrovesical approach is suitable for bilateral excision of the seminal vesicles and also for the removal of substantial benign masses.8 The surgical procedure involved median subumbilical incision, mobilization of the bladder, preparation of the parasite cyst and its intact excision together with the seminal vesicle. The following histopathological examination reconfirmed the macroscopic image of the cyst, showing a typical Echinococcus cyst.
Human echinococcosis results from parasitism by the larval stage of four Echinococcus species, of which Echinococcus granulosus (cystic hydatid disease) and Echinococcus multilocularis (alveolar hydatid disease) are the most important. Minor species are the polycystic species, Echinococcus vogeli (polycystic hydatid disease) and Echinococcus oligarthus, both from Central and South America. Human infection with E. granulosus is common throughout southern South America, the Mediterranean littoral and the Middle East, central Asia, and east Africa. Endemic foci are in eastern Europe, Russia, Australia, New Zealand, India, and the United Kingdom; in North America, foci have been reported from the western USA, the lower Mississippi valley, Alaska, and north-western Canada.
Echinococcosis is a zoonosis disease and Echinococcus cysts are caused by the E. granulosus parasite, which lives in the intestines of canines such as dogs, wolves and foxes (definitive hosts), and whose eggs are excreted with the feces of the animal and can contaminate several types of food such as vegetables, in turn infecting humans or other herbivorous mammals such as sheep, cattle, etc. (intermediate hosts). The eggs of the parasite are swallowed with food and then liberated embryos penetrate the intestinal mucosa, enter the portal circulation and are finally carried to the liver, where they become hydatid cysts (65% of all cysts). Some embryos (25%) reach the lungs and form pulmonary hydatids.9 Finally there is another 10% of rare locations such as brain, bones, kidneys, spleen.10 According to Medline, there are 29 cases of hydatid cysts in the pelvis mainly concerning the uterus, fallopian tubes, ovaries and seminal vesicles. The cyst wall has three layers: an inner germinal layer that gives rise within the cyst to germinal elements, a supporting intermediate layer, and an outer layer produced by the host. Some cysts die spontaneously; others may persist unchanged for years. Part or all of the inner layer of the cyst may calcify, which does not necessarily mean cyst death.
The patients are usually asymptomatic, unless symptoms occur due to pressure on adjacent organs – such as in this case (acute retention). The most characteristic radiological finding is the partial or total calcification of the cyst, which is considered pathognomonic, but it was not present here.