Multivesicular Cysts Research Articles

Success in managing a giant hepatic hydatid cyst: a case report of successful conservative surgical intervention in an endemic setting

Introduction and importance: Echinococcosis, also known as a hydatid cyst, arises from a parasitic infection caused by the larval form of the tapeworm Echinococcus granulosus in humans. This endemic disease in Tunisia presents a significant public health challenge. The case highlights the enormous size of the liver hydatid cyst, emphasizing the importance and success of conservative surgical treatment. Case Presentation: A 45-year-old female shepherdess presented with abdominal pain and a mass, diagnosed as a giant hepatic hydatid cyst. A computed tomography scan revealed a dysmorphic liver with a large multivesicular cyst. Surgical intervention included the resection and closure of multiple cystic fistulas. Postoperative recovery was uneventful and at the 6-month follow-up, the patient displayed no indications of recurrence. Clinical discussion: Echinococcosis, prevalent in livestock-farming regions, primarily affects the liver and lungs. It often remains asymptomatic, detected incidentally. Diagnosis relies on imaging, with surgical excision as the primary treatment. Percutaneous options exist but are less effective. Serologies are underused. Management challenges include complications and recurrence. Conservative surgery is common but faces complications. Radical surgery is more effective, albeit complex. Albendazole preoperatively proves promising, reducing cyst viability. Regular follow-up is crucial for recurrence detection. Conclusion: Managing giant hepatic hydatid cysts requires tailored approaches, especially in endemic regions. Our success with conservative surgical treatment highlights its effectiveness in confronting formidable cyst sizes, informing clinical practice, and contributing to the medical literature.

Hydatid Cyst of the Floor of the Mouth: A Case Report

The occurrence of a hydatid cyst in the face is rare. We report the case of a 24-year-old male with a slow-growing swelling in the floor of the mouth. The patient's history revealed chest drainage from a ruptured pulmonary abscess four years ago, without a documented bacteriological diagnosis. Clinical examination found a non-inflammatory and encapsuled swelling lifting the tongue without adenopathy. MRI scan showed a well-encapsuled multivesicular cyst (05 x 04 cm). Needle aspiration for cytology and hydatid serology were inconclusive. A complete blood count (CBC) and chest radiography revealed no abnormality. The cyst was entirely removed, and the histopathological examination conclusion was compatible with hydatid disease, which confirmed our thoughts regarding the patient's history.

Results of minimally invasive treatment of liver echinococcosis in comparison with traditional surgical methods

Aim. To analyze the effectiveness of PAIR in comparison with traditional surgical methods.Materials and methods. A retrospective analysis of 199 patients who underwent surgical treatment of hepatic echinococcosis was carried out. Pericystectomy was performed on 95 (47.7%) patients (1st group), traditional echinococcectomy – 55 (27.6%; 2nd group), PAIR – 49 (24.6%; 3rd group). All patients received antihelmintic therapy for 2 months in the postoperative period.Results. Patients of the group 3 had significantly more CE1 cysts compared with the groups 2 and 1 – 38 (77.5%) versus 19 (34.5%) and 44 (46.3%; p < 0.05) respectively. In group 2, CE2 and CE3 cysts were predominant. The duration of the operation in group 3 was significantly shorter than in group 1 and 2 – 58.2 (25–170), 194.8 (85–440) and 217 (75–540) minutes (p < 0.05). In group 1, intraoperative blood loss was higher than in group 2 – 165.4 ml (10–1000) and 106.7 ml (10–500; p < 0.05). There were no statistically significant differences between the groups in postoperative complications according to Clavien–Dindo. The duration of postoperational hospital stay of patients from the group 3 was shorter than for 1 and 2 groups – 4.3 (2–11) days, 8.03 (5–16) days and 8.08 (4–20) days (p < 0.05) respectively. There was no disease recurrence during the follow-up period.Conclusion. The optimal treatment should be based on the stage of the disease. In CE1, the most effective method is PAIR, which is characterized by a shorter postoperational hospital stay and early recovery. In multivesicular cysts (CE2-CE3b), traditional methods of treatment are effective.

Degree of calcification and cyst activity in hepatic cystic echinococcosis in humans

To evaluate the relationship between cyst activity and calcification degree in cystic echinococcosis (CE) in humans, 99 hepatic cysts at successive stages of involution, surgically excised from 72 Sardinian patients, have been analyzed. Cysts were classified into 4 groups according to calcification extent: CALC 0 (no calcification); CALC 1 (scattered punctate calcifications); CALC 2 (large coarse segmental/partial calcifications); CALC 3 (complete or nearly complete circumferential ring of calcification up to thick wall of osseous consistency/calcified content of cyst). In addition the possible correlation with antibody response has been explored analyzing IgG1, IgG4 and IgE produced against somatic PSCAg. Results showed that calcification is not restricted to the inactive WHO cyst types CE4 and CE5, but occurs to a varying extent in all morphotypes of metacestode, from active classic unilocular or multivesicular cysts to the more complicated and highly degenerate stages, where cyst wall appears massively calcified. Prevalence of calcification increases with progression of cyst degenerative process, but is not synonymous with parasite inactivity and can be misleading as signs of calcification may coexist with still metabolically active cysts. On the contrary, detection of entirely firmly solidified content seems a reliable indication of cyst inactivity. IgG4 is the dominant isotype associated particularly with the evolutive phase. Positive rates and OD levels, higher in active vs inactive stages, are stable or increase slightly in weakly and moderately calcified cysts (CALC 1/CALC 2), compared to non-calcified ones (CALC 0), strongly decreasing in highly calcified forms (CALC 3). In conclusion, evaluation of calcification extent may be pertinent for staging CE, and immunological tests, particularly for IgG4, and IgE may help to better define cyst activity.

Severe Vascular Complications Due to Liver Hydatid Cyst Relapse: A Case Report and Review of the Literature

Vascular complications of liver hydatidosis are infrequent but severe. We present a case with severe vascular problems due to a recurrence of a liver hydatid cyst. A 39 year-old male consulted the Emergency Department after frank hematemesis due to esophagealvarices. He had undergone surgery at the age of seven in his native country for liver and lung hydatid cysts. Abdominal CT showed a 20 cm multivesicular cyst, occupying segments IV, V and VIII of the liver, displacing and partially compressing a dilated portal vein and causing portal hypertension and obstruction of the inferior cava vein. A subtotal cystectomy was performed. After surgery, portal vein flow was normal and esophagealvarices disappeared, but caval obstruction remained. We review the vascular complications due to liver hydatidosis, focusing on therapeutic management. performed a subtotal cystectomy and left a lar ge drain in the cyst cavity. Postoperatively, the patient presented low output biliary fistula that did not require any treatment. The microbiological study of the liquid of the cyst confirmed Echinococcusgranulosus infestation.

Cystic Echinococcosis in the Liver: Evaluation of Percutaneous Treatment

Aim: The objective of this manuscript is to demonstrate the efficacy of PAIR in the treatment of liver echinococcal cysts, and to present the method to define the cysts inactivity after therapy, based on US images of the cyst during the post intervention evaluation. methods: We report the results of 62 liver cysts, type 1, 2 and 3a (WHO-IWGE US classification) treated by PAIR combined with Albendazole therapy, between 2003 and 2008, in the General Surgery Department and Radiology Department of the Pulido Valente Hospital (Lisbon-Portugal). All cysts were submitted to a final evaluation at five years follow-up. To evaluate the therapeutic efficacy we based in the US images. The US criteria for the therapeutic efficacy evaluation are: the parasite’s layers detachment immediately after PAIR; the diminution of the liquid area and its substitution by a solid pattern giving the cyst a pseudotumoral aspect; the modification of the US pattern of the cyst with the progressive solidification of the cyst content; and, sometimes, the cyst vanishing or observation of a linear echoic scare (vestiges). The percentage of the solidified area was determined by Computer Assisted Design (CAD) program. The cyst inactivity was defined if the cyst content solidification was total or almost total (> 90%). Results: The final evaluation of the 62 cysts showed a therapeutic efficacy of 87.1% (54 cysts), from which 48 (77.4%) reached a solidified pattern greater than 90% and six (9.7%) vanished. From the remaining nine cysts, three (4.8%) were referred to surgery in the second and third evaluations due to no alteration of its pattern (all cysts type 2); two (3.2%) reached solidification lower than 90%; and three (4.8%) relapsed (cysts type 2). No major complications or mortality were observed, neither secondary echinococcosis after PAIR. Conclusion: PAIR is an effective and safe method to treat cysts type 1 and 3a of the WHO-IWGE US classification. The efficacy was 96.2% in cysts type 1 and 95.8% in cysts type 3a. It is not indicated in multivesicular cysts (type 2), in which the therapeutic failure was 50%.

Multidetector CT and MR imaging cardiac hydatidosis: case report and review of the literature

Cardiac hydatid cysts are uncommon but potentially fatal. We present a case of isolated unilocular and multivesicular hydatid cysts in the heart, and provide a literature review of this rare condition. A 35-year-old man presented to our cardiology unit with acute chest pain. Computed tomography showed two cystic lesions in the heart. One unilocular cyst was located close to the left atrium and compressed the pulmonary artery. The other multivesicular cyst adhered to the left ventricle and displaced the left coronary arteries. T2-weighted magnetic resonance images revealed lesions in the pericardial cavity with bright signal intensity. Dot immunogold filtration assay was performed, and positive results for anti-EgCF antibody, anti-EgP antibody and anti-EgB antibody for cystic hydatidosis were found. Cardiac hydatidosis was diagnosed because of typical imaging findings and positive serology. The patient underwent surgical excision of the cysts. Postoperatively, symptoms of the patient resolved.

Multivesicular cysts in cattle: Characterisation of unusual hydatid cyst morphology caused by Echinococcus granulosus

Echinococcus granulosus, the causative agent of cystic echinococcosis, not only often causes unilocular cysts in intermediate hosts, but also in rare cases induces formation of multivesicular cysts which have similar morphology to alveolar cysts. The aim of the present study was to characterise multivesicular and unilocular hydatid cysts in cattle using morphologic and molecular diagnostic tools. Multivesicular cysts were detected in 4 out of 1255 slaughtered cows. Four unilocular cysts were also included in the study to compare with multivesicular cyst morphology. For histopathological evaluation, tissues were fixed in 10% neutral formalin. Following a routine histological tissue-processing procedure, samples were embedded in paraffin blocks and serial sections were cut at a thickness of 4–5 μm. For polymerase chain reaction (PCR), cyst walls and/or protoscolices recovered from six materials were preserved in 70% alcohol. Histopathologically, severity of calcification, fibrous capsule formation and giant cell layer were similar for multivesicular and unilocular cysts. However, the severity of subcapsular inflammation, inflammatory cell infiltration into adjacent organ parenchyma and eosinophil leucocyte infiltration into the cyst lumen was higher in multivesicular cysts. PCR analyses revealed that all unilocular hydatid cysts as well as two out of four multivesicular cysts were G1 genotype of E. granulosus. Molecular diagnosis of the other two multivesicular structures remained inconclusive as DNAs obtained from paraffin-embedded cyst walls were fragmented to small parts, as short as 100 bp, which were not suitable for PCR analyses. In conclusion, molecular analysis concomitant to histopathological examinations is useful in differential diagnosis of multivesicular echinococcosis.

Clinical and sonographic management of viable hydatid liver cysts

Aim The aim of this study was to review our 18-year experience in the treatment of viable hydatid liver cysts (HLCs) with double percutaneous aspiration and ethanol injection (D-PAI) and to provide indications for the clinical management of HLCs. Materials and methods From January 1989 to December 2007, 127 patients (100 males; 13–80 years) with 184 viable HLCs (137 univesicular, 47 multivesicular; 2.8–20 cm) underwent D-PAI. Results Ultrasonography (US) showed complete disappearance of 125/184 (68%) cysts; in the remaining 59 cases, an inactive solid (37 cases, 20%) or liquid pattern (22 cases, 12%) was observed with volume decreases of 50–80%. The final US pattern was unmodified during the follow-up in 96.8%. Local recurrences were observed in 5 patients (3.9%): 4 patients with 8 multivesicular cysts and 1 patient with a bilocular cyst (with a solid pattern on US) that ruptured into the biliary tree 2 years after the procedure and disappeared after endoscopic sphincterectomy. The mortality rate was 0.8%, and the overall morbidity was 8.6%. The mean hospital stay was 2.9 days. The time of healing for smaller cysts (<5 cm) was shorter than that of large cysts (≥5 cm) ( P < 0.001). Conclusion Our long-term results confirm the high effectiveness of D-PAI in the treatment of HLCs. These results suggest that multilocular cysts require closer follow-up than unilocular cysts.

Ultrasound Wall-Sign in Pulmonary Echinococcosis (New Application)

We report our experience in diagnosing pulmonary cystic echinococcosis using an ultrasound sign related to the cystic wall. 40 patients with 46 cysts, suspected of pulmonary echinococcosis, based on plain chest radiographs and clinical findings, were examined by ultrasound over a 9-year period (1996 - 2004), and followed up until discharge. We applied our long experience with echinococcal cysts utilising the wall sign (WS) to diagnose pulmonary hydatid disease. All cysts were subject to surgical removal, and postoperative histopathology was the gold standard. There were 34 (74 %) unilocular and 12 (26 %) multivesicular echinococcal cysts. In the univesicular cysts, the WS was found in 20 cases (66.7 %) while it was present in all multivesicular cysts (100 %). Following surgical removal, echinococcosis was confirmed by histopathology in all cases. We conclude that a double layered border in univesicular and double layered internal septum in multivesicular pulmonary echinococcal cysts is a reliable indicator of pulmonary echinococcosis, with a specificity of 66 % and 100 %, respectively.

Percutaneous treatment of univesicular versus multivesicular hepatic hydatid cysts

Percutaneous drainage has been used successfully to treat hepatic hydatid cysts. This study aimed to analyze the results of this method in the treatment of univesicular and multivesicular hepatic hydatid cysts. Ultrasound-guided percutaneous drainage was used to treat 72 patients (44 women and 28 men; average age, 46.8 +/- 17.7 years) with hepatic hydatidosis. Of these 72 patients, 57 had one cyst, 7 had two cysts, and 8 had three cysts. Albendazole (10 mg per kg of body weight daily for 8 weeks) was administered to all the patients. Serial assessments included clinical and biochemical examinations, ultrasonography, and serologic tests for echinococcal antibody titers. During the follow-up period, the mean cyst diameter decreased from 83.3 +/- 38.6 mm to 11.1 +/- 16.0 mm (p < 0.001) in the multivesicular group (27 cysts) and from 65.5 +/- 27.5 to 5.9 +/- 13.0 mm (p < 0.001) in the univesicular group (68 cysts). The final cyst diameter did not differ significantly between the two groups (p = 0.1). The findings showed that 81% of the cysts in the univesicular group and 63% in the multivesicular group disappeared (p = 0.12). The mean hospital stay was 4.8 +/- 2.9 days in the univesicular group and 6.1 +/- 4.7 days in the multivesicular group (p < 0.001). After an initial rise, the echinococcal-antibody titers fell progressively, and at the last follow-up evaluation were negative (<1:160) for 43 patients (94%) in the univesicular group and 19 patients (73%) in the multivesicular group (p = 0.03). Mild nonfatal complications were experienced by 24 patients (33%). Percutaneous drainage combined with albendazole therapy is an effective and safe method for managing hydatid cysts of the liver that requires a short hospital stay. Disappearance of the cysts depends on cyst size. Multivesicular cysts have a more complicated course, a slower disappearance, and a higher incidence of positive echinococcal-antibody titers. Abscess formed after the procedure can be treated successfully by percutaneous drainage.

Echinococcus multilocularis in musk rat (Ondatra zibethicus): the first finding of the parasite in naturally infected rodent in the Slovak Republic

Abstract Infection with the larval stage of Echinococcus multilocularis was diagnosed in musk rat (Ondatra zibethicus) in the Slovak Republic. At necropsy, massively enlarged liver with numbers of abscess-like lesions up to 1.5 cm in diameter was found. Histological examination shoved the presence of typical multivesicular cysts with multiple protoscoleces and typical laminated layer. Polymerase chain reaction confirmed the diagnosis. According to our knowledge, this is the first documentation of Echinococcus multilocularis in naturally infected rodent in territory of the Slovak Republic.

Viability and Fertility of Human Hepatic Hydatid Cysts

The adequate treatment for hydatidosis requires a knowledge of certain aspects related to the survival of infectious agents, especially protoscoleces. The aim of this study is to evaluate the viability of protoscoleces in human hepatic hydatid cysts in order to determine the prevalence of their fertility and to study the association with variables typical of the host and of the parasite. A cross-sectional study was done in biological material (the fluid from human hepatic hydatid cysts). The viability criteria used were: ovoid form, invaginated scolices and intact calcareous corpuscles, the presence of vibrating movements, and the absence of "vital" staining. The cysts were grouped as univesicular cysts (UVC), multivesicular cysts (MVC) and abscessed cysts (LAHO). Fertility was defined as living protoscoleces in relation to the total number of protoscoleces. Descriptive statistics were for the calculation of the prevalence of fertility, analytical statistics for the comparison of groups, and a multivariate analysis for the examination of the association between cyst fertility and clinical variables. A total of 163 cysts with a median diameter of 15 cm were studied in this way. Of these lesions, 79 (48.5%) were UVC, 54 (33.1%) MVC, and 30 (18.4%) LAHO. On 99 occasions (60.7%), macroscopic communication was evident in the bile duct, and a prevalence of general fertility of 57.1% (94.4% for MVC, 53.2% for UVC, and 0% for LAHO, with a value of P<0.001). Association with location, type, and diameter of the cyst, and presence of biliary communications was verified by applying a bivariate analysis, and association between fertility and the variables of the type of the cyst and the existence of biliary communications was verified employing a multivariate analysis (P values of 0.004 and <0.001, respectively). The prevalence of fertility found was low. The main prevalence of fertility was observed in MVCs. Fertility is associated with the type of cyst and the presence of biliary communications.

Preoperative Albendazole and Scolices Viability in Patients with Hepatic Echinococcosis

To determine the plasmatic and intracystal concentrations of albendazole sulfoxide (AS) and correlate them with the viability of the scolices in patients surgically treated for hepatic hydatid cysts (HHC) that received albendazole preoperatively, as an indirect way of evaluating the scolicide efficacy of the drug. A non-consecutive series of patients with uncomplicated HHC, underwent operation at the Department of Surgery, Regional Hospital of Temuco, Chile, between 2001 and 2002. The patients were given 10 mg/kg/day of albendazole for 4 days prior to the surgery. Intraoperative samples of venous blood and hydatid fluid were taken, in which the plasmatic concentration (PIC) and intracystal concentration (ICC) of AS were measured by means of high-performance liquid chromatography. With the remaining hydatid fluid, the viability of the scolices was examined. The following variables were taken into consideration: diameter, type of cyst, number of cysts, and development of cyst-biliary communications. Descriptive statistics were used in the calculation of medians, averages, and standard deviations, and analytical statistics were used for the comparison of continuous variables applying the t-test and the Mann-Whitney U-test. A total of 26 patients with HHC, with a median age of 39.5 years (range: 16-80 years); 16 were women (61.5%). Nineteen patients presented only one cyst (73.1%), and the diametric median of the cysts was 14.5 cm (range: 7-30). Fourteen patients presented univesicular cysts (53.9%), and the remaining 12 had multivesicular cysts (46.1%). The average PIC of AS in the whole series was 1.88 +/- 0.5 microg/ml and the ICC was 0.26 +/- 0.2 microg/ml. The ICC in viable hydatid cysts was 0.25 microg/ml versus 0.28 microg/ml in non-viable cysts (p = 0.7556). The absence of association between intracystal levels of AS and the viability of the scolices allows one to posit indirectly that albendazole is ineffective as a scolicidal agent administered preoperatively for 4 days.

Diagnosis and treatment of Hepatic echinococcosis: an overview

Background: Surgery has long been considered the first-choice treatment in patients with echinococcosis of the liver. The poorly predictable outcome of older studies using mebendazole or albendazole confirmed this belief. Since the introduction of a percutaneous technique (PAIR; puncture, aspiration, injection, reaspiration) treatment policy is changing. The actual question is which treatment is preferred in which patients. Methods: Review of recent literature. Results: Laparoscopic treatment of anteriorly located hepatic cysts is a new surgical technique with high success rates (77%-100%) and low complication (0%-17%) and recurrence rates (0%-9%). Albendazole is superior to mebendazole treatment. Degenerative changes were found in 82% of patients treated with albendazole and in 56% of those treated with mebendazole. The main problem is the high relapse rate: 25% mostly within 2 years. PAIR proved to be superior to albendazole treatment (88% versus 18%) and equally effective as surgery (86% versus 76%). A combined injection of alcohol with polidocanol is a simple alternative to PAIR. Percutaneous evacuation of cyst content (PEVAC) made percutaneous treatment accessible to patients with complicated cysts. Conclusions: Albendazole is the first-choice treatment in patients with univesicular cysts. PAIR or combined injection of alcohol with polidocanol is indicated when pain is intractable or albendazole fails. In patients with multivesicular cysts, PEVAC is a better choice. Surgery is the first-choice treatment only when the expertise of percutaneous treatment is not available or when percutaneous treatment fails.

A CASE OF CYSTIC HYDATID DISEASE OF THE LIVER DIAGNOSED BEFORE SURGERY

Cystic hydatid disease of the liver has been unusual in Japan. However, the recently increasing immigration from endemic areas might lead to a rise in the prevalence of this disease in Japan. We report a case of cystic hydatid disease of the liver which was diagnosed preoperatively. A 28-year-old nepalese man was admitted with a chief complaint of abdominal discomfort. He had lived in Nepal 2 months before. A tumor 8×12cm in size was palpated in the upper abdomen. Mild eosinophilia and increased biliary enzymes were observed. Abdominal US and CT revealed two large multivesicular cysts with thin septa in the left lobe of the liver, and a univesicular cyst in the left medial and right anterior inferior segment of the liver. MRI showed well-defined, low-intensity rims which surrounded each cyst on a T2-weighted image. From these findings and his history, we diagnosed hepatic hydatid disease. The diagnosis was confirmed by serological testing. Extended left hepatic lobectomy was performed. Protoscoleces of Echinococcus granulosus were detected in the serouns fluid aspirated from the cyst.

Comparison of Serodiagnostic Tests and Ultrasonography for Cystic Hydatidosis in an Epidemiological Study of Rural Uruguay

Cystic hydatidosis (CH) caused by Echinococcus granulosus is an important zoonosis worldwide. Several serodiagnostic and ultrasound tests are currently used for screening asymptomatic CH. The sensitivity of the serodiagnostic tests has been demonstrated by several groups to be lower than ultrasonography (US). To explain the mechanism of the difference in sensitivity, a large-scale US survey combined with an IgG4-enzyme-linked immunosorbent assay test was conducted in Uruguay. Our results suggest that certain cyst images, e.g., multivesicular cysts, may be closely associated with a high antibody response regardless of the cyst size, whereas other hydatid lesions, e.g., solid images with/without rolled parasite membranes, have lower antibody responses with a close relationship to cyst size. Seropositivity of subjects who had been treated surgically for removal of hydatid cysts in the last 5 yr was closest to that of actual CH patients, albeit free from CH by US. These findings are important for the proper use of serodiagnostic tests and US for community-based epidemiological studies.

Sonographic findings in hydatid disease of the liver: comparison with other imaging methods

Patients with hepatic hydatid disease were examined by sonography (N = 62), plain radiography (N = 62), computerized tomography (CT; N = 25) and/or isotope scans (N = 31). The clinical presentation ranged from asymptomatic to right upper quadrant complaints and, rarely, remote symptoms. Plain radiology showed liver calcifications in 26% of the cases tested; half of the calcifications were in collapsed, flattened cysts. Sonography, the investigation of choice, since it is cheap, non-invasive and accurate, is particularly useful during the active stage of cyst development, when plain X-rays appear normal or show non-specific hepatomegaly. Sonography was used to categorize cysts as 'solitary univesicular' (23% of cases, echo-free, with sand or split wall), 'solitary multivesicular' (31%), 'solid echogenic mass' (10%), 'multiple' (21%); either uni- or multi-vesicular) or 'collapsed, flattened and calcified' (16%). Sonography was superior to CT in the investigation of the cyst wall, hydatid 'sand', daughter cysts, and the relationship of the cyst to the diaphragm. However, CT was superior to sonography in detecting gas within the cysts and minute calcifications and in anatomical mapping. The majority of the hydatid cases had multivesicular cysts. In Jordan, as in all endemic areas, a univesicular cyst of the liver should be considered a possible Echinococcus granulosus infection until proven otherwise.

Hydatid Disease of the Urinary Tract: Evaluation of Diagnostic Methods

Eight patients with histologically proven hydatid disease of the urinary tract underwent eosinophil count, ultrasonography (US) and computed tomography (CT). The findings were compared with those in 8 age-matched controls with simple renal cysts. Eosinophilia was not significantly different in the 2 groups. Mixed echogenicity on US and multivesicular cyst with mixed density on CT were the diagnostic features of hydatid cysts. Using these factors, both US and CT could diagnose or exclude hydatid disease in a significant number of patients with renal cysts. However, CT was more sensitive (88 vs 50%) and accurate (94 vs 75%) than US in the diagnosis of urinary tract hydatid disease. Retrograde pyelography confirmed communicating renal hydatid cysts in 2 patients. A practical algorithm for the investigation of urinary tract hydatid disease is suggested.

In vivo cultivation of Echinococcus multilocularis protoscoleces in micropore chambers

Micropore chambers containing unevaginated protoscoleces of E. multilocularis were implanted into the peritoneal cavity of AKR mice. Transformation from protoscoleces to fertile multivesicular cysts was obtained after 210 days. Ultrastructural observations of these morphological transformations indicate that a phase of histogenesis follows a phase of dedifferentiation. This morphogenetic process raises the question of the origin of new cell populations. The results reveal the potential role of protoscoleces in secondary echinococcosis and the value of this experimental model for further studies on the larval development.