Hepatic infestation of Echinococcus multilocularis with extension to regional lymph nodes

Hydatid cyst of the humerus presenting as a suspicious lesion: A rare case report and review of literature

Hydatidosis is a parasitic disease caused by the tapeworm Echinococcus. Echinococcus Granulosus is the most common cause of hydatid disease in humans. Bone involvement is rare, accounting for only 0.9% to 2.5% of all cases. We report the case of an 8-year-old child admitted with right arm pain, revealing a hydatid cyst on the humerus. Lesion assessment revealed a hydatid cyst of the humerus with extension to the adjacent soft tissues. The surgical procedure involved the excision of the cyst along with drainage. In this case report, we review the epidemiological, clinical, and paraclinical aspects of the disease, as well as the treatment modalities. Bone hydatid disease is infiltrative, diffuse, slow, and progressive, making diagnosis late, and compromising the quality of treatment.

A CT-based radiomics model for predicting lymph node metastasis in hepatic alveolar echinococcosis patients to support lymph node dissection

BACKGROUND

Hepatic alveolar echinococcosis (AE) is a severe zoonotic parasitic disease, and accurate preoperative prediction of lymph node (LN) metastasis in AE patients is crucial for disease management, but it remains an unresolved challenge. The aim of this study was to establish a radiomics model for the preoperative prediction of LN metastasis in hepatic AE patients.

METHODS

A total of 100 hepatic AE patients who underwent hepatectomy and hepatoduodenal ligament LN dissection at Qinghai Provincial People's Hospital between January 2016 and August 2023 were included in the study. The patients were randomly divided into a training set and a validation set at an 8:2 ratio. Radiomic features were extracted from three-dimensional images of the hepatoduodenal ligament LNs delineated on arterial phase computed tomography (CT) scans of hepatic AE patients. Least absolute shrinkage and selection operator (LASSO) regression was applied for data dimensionality reduction and feature selection. Multivariate logistic regression analysis was performed to develop a prediction model, and the predictive performance of the model was evaluated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

RESULTS

A total of 7 radiomics features associated with LN status were selected using LASSO regression. The classification performances of the training set and validation set were consistent, with area under the operating characteristic curve (AUC) values of 0.928 and 0.890, respectively. The model also demonstrated good stability in subsequent validation.

CONCLUSION

In this study, we established and evaluated a radiomics-based prediction model for LN metastasis in patients with hepatic AE using CT imaging. Our findings may provide a valuable reference for clinicians to determine the occurrence of LN metastasis in hepatic AE patients preoperatively, and help guide the implementation of individualized surgical plans to improve patient prognosis.

Fifty-five cases of hepatic alveolar echinococcosis combined with lymph node metastasis: A retrospective study

BACKGROUND

Lymph node metastasis is a specific type of metastasis in hepatic alveolar echinococcosis (AE). Currently, there is a scarcity of describing the clinical characteristics and lymph node metastasis rules of patients with hepatic AE combined with lymph node metastasis and its mechanism and management are still controversial. Radical hepatectomy combined with regional lymph node dissection is a better treatment.

AIM

To analyse the clinical features of hepatic AE combined with lymph node metastasis to explore its treatment and efficacy.

METHODS

A total of 623 patients with hepatic AE admitted to the First Affiliated Hospital of Xinjiang Medical University from 1 January 2012 to 1 January 2022 were retrospectively analysed. Fifty-five patients with combined lymph node metastasis were analysed for their clinical data, diagnosis and treatment methods, follow-up efficacy, and characteristics of lymph node metastasis. Finally, we comparatively analysed the lymph node metastasis rates at different sites. Categorical variables are expressed as frequencies and percentages, and the analysis of difference was performed using the χ 2 test. The Bonferroni method was used for pairwise comparisons when statistical differences existed between multiple categorical variables.

RESULTS

A lymph node metastasis rate of 8.8% (55/623) was reported in patients with hepatic AE, with a female predilection (69.1%) and a statistically significant sex difference (χ 2 = 8.018, P = 0.005). Of the 55 patients with lymph node metastasis, 72.7% had a parasite lesion, neighbouring organ invasion, and metastasis stage of P3N1M0 and above, of which 67.3%, 78.2%, and 34.5% of hepatic AE lesions invaded the bile ducts, blood vessels, and distant metastases, respectively. Detection rates of lymph node metastasis of 16.4%, 21.7%, and 34.2% were reported for a preoperative abdominal ultrasound, magnetic resonance imaging, and computed tomography examinations. All patients were intraoperatively suspected with enlarged lymph nodes and underwent radical hepatectomy combined with regional lymph node dissection. After surgery, a routine pathological examination was conducted on the resected lymph nodes. A total of 106 positive lymph nodes were detected in six groups at various sites, including 51 single-group metastasis cases and four multi-group metastasis cases. When the metastasis rates at different sites were statistically analysed, we observed that the metastasis rate in the para-hepatoduodenal ligament lymph nodes was significantly higher than that of the other sites (χ 2 = 128.089, P = 0.000 < 0.05). No statistical difference was observed in the metastasis rate between the five other groups. Clavien-Dindo grade IIIa complication occurred in 14 cases, which improved after administering symptomatic treatment. Additionally, lymph node dissection-related complications were not observed. Recurrence after 2 years was observed in one patient.

CONCLUSION

Lymph node metastasis is a rare form of metastasis in hepatic AE, which is more frequent in women. Para-hepatoduodenal ligament lymph nodes are commonly observed. Radical hepatectomy combined with regional lymph node dissection is a safe, effective, and feasible treatment for liver AE combined with lymph node metastasis.

Immunization with EmCRT-Induced Protective Immunity against Echinococcus multilocularis Infection in BALB/c Mice

Alveolar echinococcosis (AE) is a severe parasitic zoonosis caused by the larval stage of Echinococcus multilocularis. The identification of the antigens eliciting acquired immunity during infection is important for vaccine development against Echinococcus infection. Here, we identified that E. multilocularis calreticulin (EmCRT), a ubiquitous protein with a Ca²⁺-binding ability, could be recognized by the sera of mice infected with E. multilocularis. The native EmCRT was expressed on the surface of E. multilocularis larvae as well as in the secreted products of metacestode vesicles and protoscoleces (PSCs). The coding DNA for EmCRT was cloned from the mRNA of the E. multilocularis metacestode vesicles and a recombinant EmCRT protein (rEmCRT) was expressed in E. coli. Mice immunized with soluble rEmCRT formulated with Freund’s adjuvant (FA) produced a 43.16% larval vesicle weight reduction against the challenge of E. multilocularis PSCs compared to those that received the PBS control associated with a high titer of IgG, IgG1 and IgG2a antibody responses as well as high levels of Th1 cytokines (IFN-γ and IL-2) and Th2 cytokines (IL-4, IL-5 and IL-10), produced by splenocytes. Our results suggest that EmCRT is an immunodominant protein secreted by E. multilocularis larvae and a vaccine candidate that induces partial protective immunity in vaccinated mice against Echinococcus infection.

Treatment of Complicated Hepatic Alveolar Echinococcosis Disease With Suspicious Lymph Node Remote Metastasis Near the Inferior Vena Cava-Abdominal Aorta: A Case Report and Literature Review

Echinococcosis is a human-animal parasitic disease caused by Echinococcosis tapeworm larvae in humans. From a global perspective, it is mainly prevalent in the mid-high latitudes of the Northern Hemisphere, and it is a widespread infectious disease. Its form, host and release areas are slightly different. In clinical practice, Echinococcus granulosus (hepatic cystic echinococcosis) is the most common. Its growth mode is swelling growth and its metastasis is more common in implanted metastasis; However, hepatic alveolar echinococcosis (HAE) is rare. It has been reported that HAE can metastasize through the blood or lymph nodes, and its invasive growth pattern is known as “carcinoma”. At this time, it may be accompanied by invasion of the portal vein and inferior vena cava(IVC)or metastasis to distant organs outside the liver (such as lung, brain, lymph nodes). Most patients are in the middle or late stages, making treatment complicated. World Health Organization guidelines recommend radical resection of HAE; However, there is no consensus on lymph node dissection. To date, there have been no reports of cases of HAE accompanied by inferior vena cava-para-abdominal aortic suspected lymph node metastasis and infection. This article reports a clinical case of a complex HAE treated by the surgical method of “middle liver resection + abdominal enlarged lymph node resection + inferior vena cava repair”, and histological examination was performed to illustrate the differences in microscopic pathology of alveolar echinococcosis invading the liver and lymph nodes at different magnifications. This article reviews the relevant literature on HAE and derives the latest treatment methods for HAE to provide a reference for future clinical cases of similar alveolar echinococcosis and maximize the benefits of patients.

Morphological Characteristics of Alveolar and Cystic Echinococcosis Lesions in Human Liver and Bone

Among echinococcoses diseases of human interest, two have a global public health impact: cystic and alveolar echinococcosis caused by Echinococcus granulosus sensu lato and Echinococcus multilocularis, respectively. Cystic and alveolar echinococcosis are neglected infectious diseases epidemiologically and are clinically vastly different with distinct microscopic features. Because of the rareness of these zoonotic diseases, pathologists have limited diagnostic experience in the analysis of the lesions caused by Echinococcus tapeworms. Here, we describe the main microscopic features to be considered to characterize these lesions: laminated layer, central necrosis, growth pattern, and delineation from adjacent tissue. Moreover, immunohistology using monoclonal antibodies is of great diagnostic help in reaching a definitive diagnosis by identifying the laminated body and small particles of E. multilocularis (spems) and small particles of E. granulosus (spegs).

Establishing and evaluation of a polymerase chain reaction for the detection of Echinococcus multilocularis in human tissue

BACKGROUND

Alveolar echinococcosis (AE) is caused by metacestode larva of the tapeworm Echinococcus multilocularis. AE diagnostics currently rely on imaging techniques supported by serology, but unequivocal detection of AE is difficult. Although polymerase chain reaction (PCR)-based methods to detect tapeworm DNA in biopsies have been suggested for several species, no validated protocol adhering to accepted guidelines has so far been presented for AE diagnostics. We herein established a PCR protocol for metacestode biopsies and technically evaluated the method using isolated parasite DNA and cells, biopsies of clinically relevant material, and formalin fixed paraffin-embedded (FFPE) human tissue blocks. We compared the results with an immunochemical (IHC) approach using the monoclonal antibody Em2G11 specific for the antigen Em2 of E. mulitlocularis.

METHODOLOGY/PRINCIPAL FINDINGS

Based on tapeworm 12S rDNA sequences we established and validated a PCR protocol for robust detection of as little as 50 parasite cells per specimen and report 127 cases of positive identification of Echinococcus species in samples from humans and animals. For further validation, we analyzed 45 liver, heart, brain, and soft tissue samples as well as cytological probes of aspirates of FFPE-material from 18 patients with clinically confirmed AE. Of each patient we analyzed (i) fully viable lesions with laminated layer; (ii) tissue with mAbEm2G11-positive small particles of E. multilocularis (spems); (iii) mAbEm2G11-negative tissue adjacent to the main lesion; and (iv) lymph node tissue with mAbEm2G11-positive spems. To identify the areas for the PCR-based approach, we performed IHC-staining with the monoclonal antibody Em2G11. Micro-dissected tissue of these areas was then used for PCR-analysis. 9 of 15 analyzed samples with viable E. multilocularis lesions with laminated layer were positive by PCR. Of this group, all samples preserved for less than 6 years (6/6) were tested positive. 11 of 15 samples of spems and 7 of 9 samples of the control group mAbEm2G11-negative tissue were negative by PCR. We further show that all probes from lymph nodes with spems are PCR negative.

CONCLUSIONS/SIGNIFICANCE

We present a sensitive PCR method for the detection of E. multilocularis in human tissue, particularly in fresh biopsy material and tissue blocks stored for less than 5 years. While the diagnostic sensitivity of material containing only spems was higher using IHC, PCR detection was possible in IHC negative liver tissue and in patients with negative serology. Our results support the view that spems do not contain parasitic DNA or viable cells of the parasite. spems thus most probably do not directly contribute to metastasis formation during AE.

Immunohistological detection of small particles of Echinococcus multilocularis and Echinococcus granulosus in lymph nodes is associated with enlarged lymph nodes in alveolar and cystic echinococcosis

BACKGROUND

Alveolar (AE) and cystic echinococcosis (CE) in humans are caused by the metacestode of the tapeworms Echinococcus multilocularis and Echinococcus granulosus sensu lato (s.l.). Immunohistochemistry with the monoclonal antibodies (mAb) Em2G11, specific for AE, and the mAb EmG3, specific for AE and CE, is an important pillar of the histological diagnosis of these two infections. Our aim was to further evaluate mAb EmG3 in a diagnostic setting and to analyze in detail the localization, distribution, and impact of small particles of Echinococcus multilocularis (spems) and small particles of Echinococcus granulosus s.l. (spegs) on lymph nodes.

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated the mAb EmG3 in a cohort of formalin-fixed, paraffin embedded (FFPE) specimens of AE (n = 360) and CE (n = 178). These samples originated from 156 AE-patients and 77 CE-patients. mAb EmG3 showed a specific staining of the metacestode stadium of E. multilocularis and E. granulosus s.l. and had a higher sensitivity for spems than mAb Em2G11. Furthermore, we detected spegs in the surrounding host tissue and in almost all tested lymph nodes (39/41) of infected patients. 38/47 lymph nodes of AE showed a positive reaction for spems with mAb EmG3, whereas 29/47 tested positive when stained with mAb Em2G11. Spegs were detected in the germinal centers, co-located with CD23-positive follicular dendritic cells, and were present in the sinuses. Likewise, lymph nodes with spems and spegs in AE and CE were significantly enlarged in size in comparison to the control group.

CONCLUSIONS/SIGNIFICANCE

mAb EmG3 is specific for AE and CE and is a valuable tool in the histological diagnosis of echinococcosis. Based on the observed staining patterns, we hypothesize that the interaction between parasite and host is not restricted to the main lesion since spegs are detected in lymph nodes. Moreover, in AE the number of spems-affected lymph nodes is higher than previously assumed. The enlargement of lymph nodes with spems and spegs points to an immunological interaction with the small immunogenic particles (spems and spegs) of Echinococcus spp.

Combining Computed Tomography and Histology Leads to an Evolutionary Concept of Hepatic Alveolar Echinococcosis

Alveolar echinococcosis (AE) is caused by the intermediate stage of Echinococcus multilocularis. We aimed to correlate computed tomography (CT) data with histology to identify distinct characteristics for different lesion types. We classified 45 samples into five types with the Echinococcus multilocularis Ulm Classification for Computed Tomography (EMUC-CT). The various CT lesions exhibited significantly different histological parameters, which led us to propose a progression model. The initial lesion fit the CT type IV classification, which comprises a single necrotic area with the central located laminated layer, a larger distance between laminated layer and border zone, a small fibrotic peripheral zone, and few small particles of Echinococcus multilocularis (spems). Lesions could progress through CT types I, II, and III, characterized by shorter distances between laminated layer and border zone, more spems inside and surrounding the lesion, and a pronounced fibrotic rim (mostly in type III). Alternatively, lesions could converge to a highly calcified, regressive state (type V). Our results suggest that the CT types mark sequential stages of the infection, which progress over time. These distinct histological patterns advance the understanding of interactions between AE and human host; moreover, they might become prognostically and therapeutically relevant.

Ex vivo liver resection and autotransplantation as alternative to allotransplantation for end-stage hepatic alveolar echinococcosis

BACKGROUND & AIMS

Radical resection is the best treatment for patients with advanced hepatic alveolar echinococcosis (AE). Liver transplantation is considered for selected advanced cases; however, a shortage of organ donors and the risk of postoperative recurrence are major challenges. The aim of this study was to assess the clinical outcomes of ex vivo liver resection and autotransplantation for end-stage AE.

METHODS

In this prospective study, 69 consecutive patients with end-stage hepatic AE were treated with ex vivo resection and liver autotransplantation between January 2010 and February 2017. The feasibility, safety and long-term clinical outcome of this technique were assessed.

RESULTS

Ex vivo extended hepatectomy with autotransplantation was successful in all patients without intraoperative mortality. The median weight of the graft and AE lesion were 850 (370-1,600) g and 1,650 (375-5,000) g, respectively. The median duration of the operation and anhepatic phase were 15.9 (8-24) h and 360 (104-879) min, respectively. Six patients did not need any blood transfusion. Complications higher than IIIa according to Clavien classification were observed in 10 patients. The 30-day-mortality and overall mortality (>90 days) were 7.24% (5/69) and 11.5% (8/69), respectively. The mean hospital stay was 34.5 (12-128) days. Patients were followed-up systematically for a median of 22.5 months (14-89) without recurrence.

CONCLUSION

This is the largest series assessing ex vivo liver resection and autotransplantation in end-stage hepatic AE. This technique could be an effective alternative to liver transplantation in patients with end-stage hepatic AE, with the advantage that it does not require an organ nor immunosuppressive agents.

LAY SUMMARY

Ex vivo liver resection and autotransplantation were performed in a large series of patients with end-stage hepatic alveolar echinococcosis. The results showed that this surgical option was feasible, with acceptable postoperative mortality, but 100% disease-free survival in survivors. Careful patient selection, as well as precise assessment for size and quality of the remnant liver are key to successful surgery.

Alveolar Echinococcosis Mimicking a Hepatic Neoplasm with Lymph Node Metastasis: A Case Report

A 37-year-old man had an asymptomatic 17-mm mass in the liver by health check with ultrasonography. Five years later, he was referred to our hospital because the mass was slightly enlarged with a peripancreatic lymph node. We performed endoscopic ultrasonography fine-needle aspiration (EUS-FNA) to evaluate a lymph node, but it showed amorphous eosinophilic material and eosinophilic infiltrate in necrotic tissue of toothpaste-like white specimen. However, we diagnosed as potentially malignant liver mass with lymph node metastasis because of 2-deoxy-2-(fluorine-18) fluorodeoxyglucose uptake. We then performed hepatectomy and enucleation of the pancreas. DNA polymerase chain reaction analysis revealed Echinococcus multilocularis infection. Retrospectively, we could find a part of Echinococcus in the specimens of EUS-FNA.

Impact of affected lymph nodes on long-term outcome after surgical therapy of alveolar echinococcosis

PURPOSE

Alveolar echinococcosis (AE) is a life-threatening helminthic disease. In humans, AE mostly affects the liver; the regional hepatic lymph nodes may be involved, indicating dissemination of AE from the liver. To achieve complete removal of the disease, enlarged hepatic lymph nodes may be resected during surgical treatment. We evaluated the frequency of affected lymph nodes by conventional microscopic and immunohistochemical analyses including detection of small particles of Echinococcus multilocularis (spem). Furthermore, we analyzed the association of resection of enlarged and affected lymph nodes with long-term outcome after surgical therapy of patients who underwent surgery with curative intent.

MATERIALS AND METHODS

We identified 43 patients who underwent hepatic surgery with curative intent with lymph node resection for AE. We analyzed the cohort for the manifestation of the parasite in the resected lymph nodes by conventional histology and by immunohistochemistry and compared these data with the further course of AE.

RESULTS

Microscopically infected lymph nodes (laminar layer visible) were found in 7 out of these 43 patients (16%). In more than three quarters (25/32) of all specimens investigated, lymph nodes showed spems when stained with antibody against Em2G11, a monoclonal antibody specific for the Em2 antigen of the Echinococcus multilocularis metacestode. Most frequently, lymph nodes were resected due to enlargement. The median size of microscopically affected lymph nodes was 2 cm (range, 1.2 to 2.5 cm), the median size of immunohistochemically and non-affected lymph nodes was 1.3 cm each (range, "small" to 2.3 or 2.5 cm, respectively). Median follow-up was 8 years for all patients, 5 years for patients with lymph node resection, and 4 years for patients with infested lymph nodes. Overall, recurrent disease was seen in ten patients (10/109; 9%) after a median period of 1.5 years (range, 4 months to 4 years). None of the seven patients with conventionally microscopically affected lymph nodes suffered from recurrent disease. One patient with negative resected nodes and one patient with spems showed recurrent disease after 4 and 35 months, respectively.

CONCLUSIONS

Lymph node involvement in AE is frequent, particularly when evaluated by immunohistochemical examination of lymph nodes with the monoclonal antibody Em2G11. Affected lymph nodes tend to be larger in size. Lymph node involvement is not associated with recurrent disease and therefore warrants further analysis of the biological significance of lymph node involvement.

The Echinococcoses: Diagnosis, Clinical Management and Burden of Disease

The echinococcoses are chronic, parasitic diseases that are acquired after ingestion of infective taeniid tapeworm eggs from certain species of the genus Echinococcus. Cystic echinococcosis (CE) occurs worldwide, whereas, alveolar echinococcosis (AE) is restricted to the northern hemisphere, and neotropical echinococcosis (NE) has only been identified in Central and South America. Clinical manifestations and disease courses vary profoundly for the different species of Echinococcus. CE presents as small to large cysts, and has commonly been referred to as 'hydatid disease', or 'hydatidosis'. A structured stage-specific approach to CE management, based on the World Health Organization (WHO) ultrasound classification of liver cysts, is now recommended. Management options include percutaneous sterilization techniques, surgery, drug treatment, a 'watch-and-wait' approach or combinations thereof. In contrast, clinical manifestations associated with AE resemble those of a 'malignant', silently-progressing liver disease, with local tissue infiltration and metastases. Structured care is important for AE management and includes WHO staging, drug therapy and long-term follow-up for at least a decade. NE presents as polycystic or unicystic disease. Clinical characteristics resemble those of AE, and management needs to be structured accordingly. However, to date, only a few hundreds of cases have been reported in the literature. The echinococcoses are often expensive and complicated to treat, and prospective clinical studies are needed to better inform case management decisions.

Mediastinum Lymph Node Hydatidosis

A 55 year old woman, presented to our hospital with a one year history of coughing and left chest pain. A chest CT-scan showed mediastinal, pleural and pulmonary cystic lesions evoking hydatidosis. Surgical exploration found a cystic lesion of the aorta-pulmonary window.

Extrahepatic primary adrenal alveolar echinococcosis: a review

BACKGROUND

Primary echinococcosis, and especially primary alveolar echinococcosis (AE) is rare among adrenal lesions.

METHODS

We report a case of primary AE in a 28-year-old male with low backache and occasional upper limb pain lasting for six months, and review the pertinent but sparse literature on this disorder.

RESULTS

Evaluation of the patient revealed an abdominal mass as right adrenal AE. The adrenal gland is a rare extrahepatic site of occurrence of echinococcosis, and particularly of AE. Patients with adrenal echinococcosis usually have nonspecific clinical symptoms. Imaging examinations revealed clearly the features of AE and its surrounding pathology. Alveolar echinococcosis was seen as an inhomogeneous pseudotumor with irregular boundaries, an irregular central pseudocystic appearance, and infiltration into surrounding structures. On contrast-enhanced computed tomography, the periphery of the mass in AE may be enhanced and multicentric vesicles may be seen. Magnetic resonance imaging may show the multivesicular morphology of lesions. The definitive diagnosis of AE should be confirmed by pathologic or serologic examination. Radical surgical resection of the removable parasitic lesion, followed by anti-infective therapy with benzimidazoles, is the primary method for treating AE.

CONCLUSION

Although primary adrenal AE is rare, it should be included in the differential diagnosis of adrenal masses, especially in regions where AE is endemic.

Alveolar echinococcosis-spreading disease challenging clinicians: A case report and literature review

Human alveolar echinococcosis (AE) is a potentially deadly disease; recent studies have shown that the endemic area of Echinococcus multilocularis, its causative agent, is larger than previously known. This disease has low prevalence and remains underreported in Europe. Emerging clinical data show that diagnostic difficulties are still common. We report on a 76-year old patient suffering from AE lesions restricted to the left lobe of the liver who underwent a curative extended left hemihepatectomy. Prior to the resection a liver biopsy under the suspicion of an atypical malignancy was performed. After the intervention he developed a pseudoaneurysm of the hepatic artery that was successfully coiled. Surprisingly, during surgery, the macroscopic appearance of the tumour revealed a growth pattern that was rather typical for cystic echinococcosis (CE), i.e., a gross tumour composed of multiple large vesicles with several centimeters in diameter. In addition, there were neither extensive adhesions nor infiltrations of the neighboring pancreas and diaphragm as was expected from previous imaging results. The unexpected diagnosis of AE was confirmed by definite histopathology, specific polymerase chain reaction and serology results. This is a rare case of unusual macroscopic presentation of AE that posed immense diagnostic challenges and had an eventful course. To our knowledge this is the first case of an autochthonous infection in this particular geographic area of Germany, the federal state of Saxony. This report may provide new hints for an expanding area of risk for AE and emphasizes the risk of complications in the scope of diagnostic procedures and the limitations of modern radiological imaging.

An unusual presentation of alveolar echinococcosis in a 12-yr-old immunocompetent child

AE is a parasitic disease caused by Echinococcus multilocularis (E.m.). AE is a rare form of echinococcosis and mostly seen in 50- to 70-yr-old patients. Its asymptomatic invasive tumor-like lesion development period, which lasts as much as 20 yr, is too long. Hence, this disease is very rare in children. Herein, we report an AE in a 12-yr-old girl who was not eligible for surgical treatment because of a radiological evaluation of non-resectable lesion and was scheduled for a LT.

Sensitive and specific immunohistochemical diagnosis of human alveolar echinococcosis with the monoclonal antibody Em2G11

Background

Alveolar echinococcosis (AE) is caused by the metacestode stage of Echinococcus multilocularis. Differential diagnosis with cystic echinococcosis (CE) caused by E. granulosus and AE is challenging. We aimed at improving diagnosis of AE on paraffin sections of infected human tissue by immunohistochemical testing of a specific antibody.

Methodology/Principal Findings

We have analysed 96 paraffin archived specimens, including 6 cutting needle biopsies and 3 fine needle aspirates, from patients with suspected AE or CE with the monoclonal antibody (mAb) Em2G11 specific for the Em2 antigen of E. multilocularis metacestodes. In human tissue, staining with mAb Em2G11 is highly specific for E. multilocularis metacestodes while no staining is detected in CE lesions. In addition, the antibody detects small particles of E. multilocularis (spems) of less than 1 µm outside the main lesion in necrotic tissue, liver sinusoids and lymphatic tissue most probably caused by shedding of parasitic material. The conventional histological diagnosis based on haematoxylin and eosin and PAS stainings were in accordance with the immunohistological diagnosis using mAb Em2G11 in 90 of 96 samples. In 6 samples conventional subtype diagnosis of echinococcosis had to be adjusted when revised by immunohistology with mAb Em2G11.

Conclusions/Significance

Immunohistochemistry with the mAb Em2G11 is a new, highly specific and sensitive diagnostic tool for AE. The staining of small particles of E. multilocularis (spems) outside the main lesion including immunocompetent tissue, such as lymph nodes, suggests a systemic effect on the host.

Echinococcosis is a life-threatening disease in humans that is caused by the larval stages of the tapeworms Echinococcus multilocularis and Echinococcus granulosus. The eggs of the parasites are released with faeces of canids, and humans are aberrantly infected. In humans, the larval stages of the parasites cause tumour-like lesions mainly in the liver and the lungs. Precise diagnosis of the parasite responsible for human disease is of utmost importance since therapy regimens largely differ between cystic and alveolar echinococcosis. Diagnosis is based on serology, imaging and histology, the latter being the gold standard. However, conventional histology cannot always clearly identify the causative parasite because both parasites can cause human tissue to present similar features. Therefore, we have developed the monoclonal antibody Em2G11 and an immunohistological technique that allows a cheap and fast clear-cut diagnosis of E. multilocularis even on aspirates and small archived bioptic tissue samples. Furthermore, this technique disclosed an unknown feature of human alveolar echinococosis we called "small particles of E. multilocularis" (spems). We argue that these small particles represent micro-fragments of E. multilocularis and thus point to a new form of host-parasite interaction.

Alveolar echinococcosis of the liver: report of three cases from different geographic areas of iran

INTRODUCTION

Alveolar echinococcosis (AE) is a chronic, serious and sometimes lethal parasitic infection, which is caused by Echinococcus multilocularis (EM). AE has been reported to occur in people from the north of Iran; however, until now there have been no cases of AE reportedfrom the southern provinces, such as Khuzestan.

CASE PRESENTATION

Herein, we report our experiences with three cases of hepatic AE, who presented with large masses in the liver, from both the northern and southern provinces of Iran. Three patients are described who were presented with hepatic masses from different provinces of the country.

CONCLUSIONS

There were three female patients, 21, 47 and 53 year-old. They were presented with liver masses from different centers of the country i.e. Khorasan, Ardabil and Khuzestan. According to our experience, AE is not an uncommon disease in Iran. Moreover, it has a widespread epidemiology, i.e., this disease should be suspected in all provinces of Iran, not only in the northern, but also in the southern regions of the country.

Recurrent hepatic alveolar echinococcosis: report of the first case in Korea with unproven infection route

Human alveolar echinococcosis (AE), a hepatic disorder that resembles liver cancer, is a highly aggressive and lethal zoonotic infection caused by the larval stage of the fox tapeworm, Echinococcus multilocularis. E. multilocularis is widely distributed in the northern hemisphere; the disease-endemic area stretches from north America through Europe to central and east Asia, including northern parts of Japan, but it has not been reported in Korea. Herein, we represent a first case of AE in Korea. A 41-year-old woman was found to have a large liver mass on routine medical examination. The excised mass showed multinodular, necrotic, and spongiform appearance with small irregular pseudocystic spaces. Microscopically, the mass was composed of chronic granulomatous inflammation with extensive coagulation necrosis and parasite-like structure, which was revealed as parasitic vesicles and laminated layer delineated by periodic acid-Schiff (PAS) stain. Clinical and histologic features were consistent with AE. After 8 years, a new liver mass and multiple metastatic pulmonary nodules were found and the recurred mass showed similar histologic features to the initial mass. She had never visited endemic areas of AE, and thus the exact infection route is unclear.

Liver alveolar echinococcosis metastasized to the breast

BACKGROUND

Alveolar echinococcosis (AE) is a potentially fatal and chronically progressive infestation produced by the multivesicular metacestode of Echinococcus multilocularis, which most commonly affects the liver, lungs, and brain.

CASE REPORT

We present a case of AE in which an alveolar cyst, as a result of exophytic growth, adhered to intra-abdominal and pelvic organs and metastasized to the breast. Exploration showed that the exophytic cyst in the liver filled the entire abdominal cavity, reaching to the uterus and bladder, and was adherent to the neighboring tissues and organs. This cystic lesion was totally excised, as was the 7×6 cm cystic lesion in the right breast.

CONCLUSIONS

The liver is the most common site for echinococcal cysts of the pastoral strains (>65%), followed by the lungs (25%); the cyst is seen less frequently in the spleen, kidneys, heart, bone, and central nervous system. AE must be considered in areas where liver cysts are endemic and in the presence of a liver cyst, and the organs where a metastasis is possible must be thoroughly investigated. Furthermore, in these areas, when cystic disorders of the breast are present, AE should not be discounted among possible definitive diagnoses.

Clinical features and treatment of alveolar echinococcosis

PURPOSE OF REVIEW

Human alveolar echinococcosis is caused by the larval stage of Echinococcus multilocularis, occurring in at least 42 countries of the northern hemisphere. Recent studies in Europe and Asia have shown that the endemic area of E. multilocularis is larger than previously known and the parasite has regionally expanded from rural to urban areas. Diagnosis of alveolar echinococcosis is supported by results from imaging studies, histopathology and/or nucleic acid detection, and serology. The present review summarizes current understanding of clinical features, knowledge on appropriate treatment, and discusses ways to improve standards of care.

RECENT FINDINGS

High prevalences of this deadly disease have been discovered in surveys in parts of China. Clinical manifestations, diagnostic tools and the burden of disease were described, and are based on high case numbers. In Europe, excellent tools have been introduced, which improve disease management. Long-term observations in Switzerland provide an optimistic view, as the infection can be well controlled, if patients are cared for in specialized centres. An expert consensus summarizes the current recommendation for diagnosis and treatment of alveolar echinococcosis by the Informal Working Group on Echinococcosis of the WHO.

SUMMARY

Diagnosis and treatment of alveolar echinococcosis remains a challenge for clinicians. The updated WHO-recommendations aim to support decisions on diagnosis and treatment of alveolar echinococcosis. Anti-infective therapy is the backbone of treatment; surgery should be restricted to patients at an early stage of the disease. For the majority of cases continuous chemoprophylaxis with benzimidazoles is cost-effective and leads to a good quality of life for patients with this chronic disease.