Pictorial essay. Various locations of cystic and alveolar hydatid disease: CT appearances

Progress of research on the diagnosis and treatment of bone cystic echinococcosis

Bone cystic echinococcosis (CE) is one of the most complex and dangerous of all echinococcoses. The lack of typical imaging features and clinical manifestations makes diagnosis and treatment of this disease difficult. X-ray and computed tomography (CT) images of bone CE are similar to those of bone cysts, giant-cell bone tumors, and bone metastases, but magnetic resonance imaging (MRI) shows good diagnostic value due to excellent soft-tissue imaging features. Serological tests cannot be used as a definitive diagnostic method for bone CE due to cross-reactivity, which can lead to false-positive or false-negative results. The development of novel antigens can open new frontiers in the diagnosis of the disease. Currently, views conflict on how to diagnose and treat bone CE. Both surgical and pharmacological treatments can be used, but determining which is appropriate is difficult due to the different sites and clinical manifestations of bone CE. Radical resection is not indicated for large-bone injuries, and Pharmacotherapy becomes important. This article reviews the progress of research into the pathogenesis and clinical manifestations of, and diagnostic strategies and treatment options for, bone CE. We aimed to provide a reference for clinical diagnosis and -treatment options.

Osseous hydatid disease: A mimic of other skeletal pathologies

Hydatid disease is still endemic in several regions worldwide including Morocco, and is caused in most cases by the larval form of 2 species of the tapeworm Echinococcus: E. granulosus and E. multilocularis. Primary hydatid disease of the bone without systemic involvement is rare. The disease has a silent clinical evolution until it reaches complicated stages. Complications may include pathological fracture, neural deficit, infection, and fistulization of the abscess. Preoperative diagnosis is based on clinical history, imaging findings, and serological tests, which lack high sensitivity and specificity. Although the interpretation of imaging studies can prove to be very confusing because the bone changes evolve with time, and the nonspecificity of these findings often leads to a mistaken diagnosis. The diagnosis requires a high index of suspicion, especially in patients who reside in or travel to sheep-raising areas where hydatid disease is endemic. A high index of suspicion is necessary for the diagnosis, especially in patients that live in or travel to sheep-raising areas where hydatid disease is endemic. The treatment of choice remains surgical, following the principles of a locally malignant lesion. Chemotherapy (albendazole alone or in combination with praziquantel) is indicated when surgery is not possible or as an adjuvant treatment. The prognosis is often poor. We report the case of a 28-year-old woman with long-standing pain in the left hip joint in which the imaging findings were thought of as being either tuberculous or neoplastic. The result of a CT-guided biopsy concurred with an unexpected diagnosis of a hydatid cyst. This case highlights that in the absence of a high index of suspicion for echinococcal infection, the semblance of imaging findings of hydatid disease in the bone to those of other skeletal pathologies can lead to misinterpretation.

Vertebral and pelvic echinococcosis in northwestern China

PURPOSE

Echinococcosis remains a major economic and severe public health problem in endemic areas. Bone echinococcosis is rare, and the vertebra and pelvis are the most common sites of echinococcosis involving the skeletal. Because of the clinical severe symptoms and high recurrence rate, it brings excellent trouble to patients.

METHODS

This study retrospectively analyzed the clinical manifestations, laboratory tests, radiological findings, and treatment of 44 patients with vertebral and pelvic echinococcosis during a period of 16 years (2005-2020).

RESULTS

The mean age was 43 years (25 males, 19 females; 19-68 years). The most common symptom was pain, followed by numbness, weakness, activity limitation, and progressive paraparesis. Enzyme-linked immunosorbent assay test (ELISA) results were positive in 18 cases (75%). There are 24 cases of hydatid infection of the spine, 14 hydatid infection of the pelvis, and six hydatid infection of both vertebra and pelvis. The site of infection was 13 (29.5%) thoracic, five (11.4%) lumbar, four (9.1%) lumbosacral, seven (15.9%) sacral, 19 (43.2%) ilium, seven (15.9%) hip, six (13.6%) ischium, five (11.4%) pubis, and two (4.5%) femur, respectively. The imaging findings were cystic dilatancy, septal, and irregular bone destruction. MRI has a special value in showing the relationship between the surrounding tissues and organs of cystic bone echinococcosis. All patients were followed up for at least one year. The mean follow-up time was 3.6 years.

CONCLUSIONS

Even in epidemic areas, the incidence of bone echinococcosis is relatively rare. However, when encountering the vertebral and pelvic destruction, consider bone echinococcosis's possibility, especially for the herdsmen in endemic regions.

Primary intraosseous mandibular hydatid cyst: A case report and review of 97 cases of osseous cystic echinococcosis

OBJECTIVE

In this study, we review the reported cases of hydatid disease of the bone in terms of etiology, pathogenesis, and histopathologic, serologic, and radiographic features and management of the disease.

STUDY DESIGN

The present case study reports an extremely rare occurrence of intraosseous hydatid cysts in the orofacial region, wherein symptoms or signs of systemic hydatid disease were absent. We discuss the challenges encountered during the diagnosis and treatment of osseous hydatidosis and reviewed articles on osseous hydatidosis, including 97 cases. We also compare the aspects reported in previous cases of mandibular hydatid cyst with those of the present case.

RESULTS

Hydatid cysts were found to be present in almost every bone of the skeleton in patients (mean age of 39.95 ± 19.67 years; range, 3-76 years). A slight male preference (58.8%) was observed. A history of rural lifestyle, animal bites, and trauma in the affected bone was reported. Only 5 reports on mandibular bone have been published previously, of which 3 were primary.

CONCLUSION

Because of the lack of usual presentations and radiographic features, the presence of hydatid cysts in unusual anatomic locations makes differential diagnosis difficult. The potential risk of anaphylactic shock in susceptible individuals, high recurrence rate, and risk of secondary hydatidosis pose diagnostic and surgical challenges.

Is Hydatid Cyst with Musculoskeletal Involvement a Problem that Causes Morbidity? Long-Term Follow-Up and Functional Results

BACKGROUND

The aim of study is to evaluate the involvement characteristics of hydatid cysts, which are rarely involved the musculoskeletal system, and the results of recurrence, morbidity, and functional and mental scoring.

METHODS

We retrospectively investigated 18 patients with skeletal hydatid disease. Patients were categorized as those with bone or skeletal muscle involvement. Pre- and post-operative physical component scores (PCS) and mental component scores (MCS) on the functional Short Form 12-item Survey were recorded in these patients.We compared the functional scores, number of recurrences, and lesion volumes between patients with hydatid cyst of bone (HCOB) and those with hydatid cyst of soft tissue (HCOST).

RESULTS

This study included 11 women and 7 men with bone hydatid cysts. Patients' mean age was 38 years (range 22-70 years). Patients were followed up for a mean of 118.16 months (range 49-230 months). The mean lesion volume was 447.39 cm³ (36-1260 cm³). The 12th and 48th month PCS, the PCS was lower in the HCOB group during both periods (p = 0.04 and p = 0.001, respectively). The 48th month MCS was lower in the HCOB group (p = 0.04). Postoperative residual cysts were detected in five patients who underwent surgical treatment for bone c; all residual lesions were located in the pelvis.

CONCLUSIONS

Bone hydatid cysts are associated with high recurrence rates, and treatment is challenging. In view of the low functional results and high infection and recurrence rates observed in patients over long-term follow-up, particularly in those with pelvic hydatid cysts, we conclude that this disease is associated with significant morbidity.

Hepatic alveolar hydatid disease (Echinococcus multilocularis), a mimic of liver malignancy: a review for the radiologist in non-endemic areas

Alveolar hydatid disease or alveolar echinococcosis (AE) is caused by the parasite Echinococcus multilocularis and is increasingly seen as an imported disease in non-endemic areas such as the UK. It is rare compared to cystic echinococcosis (CE), but like CE commonly affects the liver. AE does have imaging features that can aid in diagnosis, but is often initially misdiagnosed as liver malignancy. It is usually fatal if untreated, underscoring the importance of early diagnosis. This review highlights the role of imaging in AE diagnosis with the broader objective of increasing radiologists' awareness of this unusual, but increasingly prevalent disease.

Primary hydatidosis of distal femur masquerading malignancy -A rare case

Hydatidosis is relatively uncommon entity and it rarely affects bone and joints. A rare case of primary hydatidosis (Echhinococcus granulosus infection) involving the distal femur and the knee joint in a 53 years old female is reported here. This presented as a pathological supracondylar fracture of femur. On establishment of a clinical diagnosis she was treated preoperatively with Albendazole 600 mg, daily for 3 cycles each of 21 days with a gap of 1 weeks between cycles. Two stage surgery was carried out, the first being a meticulous debridement and second a total knee replacement with cemented tumor mega-prosthesis. Postoperatively the wound healed completely without any evidence of infection and albendazole therapy was continued for three months following surgery. During the follow-up period of two and a half year, no recurrence of hydatidosis was noticed.

A Case of Echinococcal Cyst of the Lung

Echinococcosis, also known as Hydatid disease, is caused by the larvae of the tapeworm Echinococcus. It is globally prevalent and is a major clinical health concern. It is endemic in most underdeveloped regions including Asia, the Mediterranean, South America and Africa. There are four species within the genus Echinococcus, with E. granulosus and E. multilocularis being the most common, causing Cystic Echinococcosis (CE) and Alveolar Echinococcosis (AE). The clinical presentation of the disease is non-specific. It commonly involves the liver, lungs, brain and adrenal glands. Pulmonary disease is significant for its propensity to affect children and young adults. This young population accounts for ∼50% of pulmonary hydatid cysts [1]. Cysts are known to grow extensively in size. Many patients are asymptomatic and have only a solitary cyst. Symptoms arise from enlargement of the cyst and from eroding and pressure applied by the cyst to blood vessels and organs. If rupture of the cyst occurs it can lead to immunologic reactions such as asthma and anaphylaxis. Echinococcus in the lung can pose diagnostic dilemmas, as their homogeneous density and tendency to occur alone may cause them to be confused with squamous cell carcinoma, adenocarcinoma, solitary metastasis, and abscess [2]. Our case is of such a patient who was found to have a 6 cm mass in the right middle lobe (RML) found on a chest X-ray during evaluation of back pain. Echinococcus should always be included in a differential diagnosis of any mass lesions especially in immigrant populations from endemic countries.

Neurological disorders caused by two cerebral alveolar hydatid cysts in an old woman: a rare case report

Alveolar hydatid disease, caused by Echinococcus multilocularis, is a life-threatening infectious disease which primarily occurs in the liver. Intracranial hydatid disease is a rare presentation with reported incidence of ~1% of all cases. Here we reported a 60-year-old woman, with the past history of hydatid cysts in her liver, who was presented to us with progressive symptoms consist of headaches, diminished vision, cognitive disorders and delusion. She was disoriented in time, space and person. Bilateral mild papilledema and exaggerated reflexes were observed. Magnetic resonance imaging of the brain revealed two intra-axial multilucular cystic masses in the fronto-pareital and parieto-occipital regions. The patient underwent two operations and the lesions were removed without any rupture. Medical therapy with Albendazole was started. Neurological symptoms disappeared a few weeks after the surgeries. Although multiple alveolar hydatid cysts are extremely rare, they should be considered in the differential diagnosis of intracranial cystic lesions.

Pathological fracture of femoral neck in a middle-aged woman: a rare presentation of primary hydatid cyst disease in humans

Hydatid disease in humans is caused by Echinococcus granulosus. It most commonly involves the liver and, to a lesser extent, the lungs and spleen; however, it is known to involve other areas, too. Involvement of bone by hydatid cyst is rare. Here, we describe the case of a 37-year-old woman who presented with pain in the left groin and swelling in the left thigh. The radiological imaging showed a fracture of the femoral neck and cysts in the shaft of the femur. Diagnosis of hydatid cyst was confirmed on the basis of histopathology of biopsy specimens. The patient recovered after surgical excision of the cyst. This case illustrates the various sites and presentations of hydatid cyst disease, and the need to investigate for it if cystic bony lesions are encountered especially in endemic regions, as a delay in diagnosis can lead to long-term morbidity and even death.

Management of osseous cystic echinococcosis

INTRODUCTION

Osseous cystic echinococcosis (CE) is one of the most complicated and devastating conditions caused by Echinococcus granulosus. Its management is difficult and there is scant literature about it. Areas covered: A literature review was performed to provide an update on its diagnosis, treatment and follow-up. Expert commentary: In most cases diagnosis of osseous CE can only be confirmed by surgery. Osseous CE should be managed by experienced physicians and addressed as a chronic disease with therapies must be aimed at controlling the disease and its sequels or complications, rather than with a curative intent.

Multimodality imaging in diagnosis and management of alveolar echinococcosis: an update

Alveolar echinococcosis is a parasitic disease limited to the northern hemisphere. The disease occurs primarily in the liver and shows a profile mimicking slow-growing malignant tumors. Echinococcus multilocularis infection is fatal if left untreated. It can cause several complications by infiltrating the vascular structures, biliary tracts, and the hilum of the liver. As it can invade the adjacent organs or can spread to distant organs, alveolar echinococcosis can easily be confused with malignancies. We provide a brief review of epidemiologic and pathophysiologic profile of alveolar echinococcosis and clinical features of the disease. This article focuses primarily on the imaging features of alveolar echinococcosis on ultrasonogra-phy, computed tomography, magnetic resonance imaging, diffusion-weighted imaging and positron emission tomography-computed tomography. We also reviewed the role of radiology in diagnosis, management, and follow-up of the disease.

The study of biochemical profile of cyst fluid and diffusion-weighted magnetic resonance imaging in differentiating hepatic hydatid cysts from liver simple cysts

Purpose

The aim of this study was to investigate the value of biochemical profile of cyst fluid and diffusion‐weighted imaging (DWI) in differentiating hepatic hydatid cysts (HCs) from liver simple cysts.

Materials and methods

Forty‐six patients underwent MR imaging. Twenty‐nine patients had 29 hydatid cysts and 17 patients had liver simple cysts. Thirteen patients with hydatid cysts and seven patients with liver simple cysts were evaluated with cyst fluid biochemical analysis. The concentration of glucose, protein, calcium ion (Ca²⁺) electrolyte, macroscopic appearance, and parasitological sediment were evaluated in this study.

Results

In the respect of biochemical analysis cyst fluid, the concentration of glucose and calcium ion of HCs was significantly higher than that of the liver simple cysts. In the respect of DWI, in the b 1000 s/mm² value in respect of mean application data center (ADC) values, there was a statistically significant difference between HCs group (the mean value was (2.50±0.79)×10⁻³ mm/s²) and liver simple cysts group (the mean value was (2.92±0.66)×10⁻³ mm/s²). However, no statistically significant results were obtained in the ADC measurements of b 500 s/mm² between two groups.

Conclusion

The analysis of cyst fluid combined with the measurement of ADC values in the b 1000 s/mm² value could be considered a promising parameter as an alternative to the differential diagnosis of hepatic hydatid cysts from liver simple cysts.

Successful percutaneous treatment of extrahepatic cystic echinococcosis through PAIR and single puncture catheter techniques

PURPOSE

To demonstrate the successful percutaneous treatment of extrahepatic cystic echinococcosis as an alternative to surgical procedures.

MATERIALS AND METHODS

A total of 27 extrahepatic hydatid cysts in 12 patients, the spleen in 8 patients, muscles and soft tissues in 3 patients each and right adrenal gland in 1 patient were treated with PAIR (puncture, aspiration, injection, respiration) or single puncture catheterization methods. As a scolicidal and sclerosing agent, alcohol was used in all patients.

RESULTS

Of 27 extrahepatic lesions of hydatid cysts, 24 (88.9%) were Gharbi type 1 (WHO CE 1), and 3 (11.1%) were Gharbi type 2 (WHO CE 3A). Of hydatid cystic lesions, 20 with PAIR and 7 with single puncture catheterization methods were treated. No major complications developed in any patients. Abscesses were detected in two patients (16.6%). Mean total hospital stay was calculated between 1 and 14 days (mean 2.3 days). Follow-up periods ranged between 10 and 62 months (mean 22.3 months).

CONCLUSION

Percutaneous treatment for extrahepatic hydatid cystic lesions is an important alternative to surgical procedures because of the high therapeutic success rate, lower rate of complications and shorter hospital stays.

Skeletal manifestations of hydatid disease in Serbia: demographic distribution, site involvement, radiological findings, and complications

Although Serbia is recognized as an endemic country for echinococcosis, no information about precise incidence in humans has been available. The aim of this study was to investigate the skeletal manifestations of hydatid disease in Serbia. This retrospective study was conducted by reviewing the medical database of Institute for Pathology (Faculty of Medicine in Belgrade), a reference institution for bone pathology in Serbia. We reported a total of 41 patients with bone cystic echinococcosis (CE) during the study period. The mean age of 41 patients was 40.9±18.8 years. In 39% of patients, the fracture line was the only visible radiological sign, followed by cyst and tumefaction. The spine was the most commonly involved skeletal site (55.8%), followed by the femur (18.6%), pelvis (13.9%), humerus (7.0%), rib (2.3%), and tibia (2.3%). Pain was the symptom in 41.5% of patients, while some patients demonstrated complications such as paraplegia (22.0%), pathologic fracture (48.8%), and scoliosis (9.8%). The pathological fracture most frequently affected the spine (75.0%) followed by the femur (20.0%) and tibia (5.0%). However, 19.5% of patients didn't develop any complication or symptom. In this study, we showed that bone CE is not uncommon in Serbian population. As reported in the literature, therapy of bone CE is controversial and its results are poor. In order to improve the therapy outcome, early diagnosis, before symptoms and complications occur, can be contributive.

Hydatid Disease of the Femur with an Extraosseous Extent due to a Former Biopsy Complicated by a Pathological Fracture

Hydatid disease of the bone represents about 1–2.5% of all human hydatid disease. Spine is the most affected part of the skeleton with 50% incidence of all bone hydatidosis. Extraspinal bone hydatidosis is much rare. Diagnosis is difficult in the bone hydatid disease. Bone tumors, tumor-like lesions, and specific and nonspecific infections should be considered in the differential diagnosis. Radiological, laboratory, and clinical findings combined with strong element of suspicion are the key for diagnosis. Bone biopsies should be avoided because of the danger of anaphylaxis, sensitization, and spread. This paper describes the management of a patient with primary hydatidosis of the femur, which had been complicated by an extraosseous involvement, cortical erosion, and a pathological fracture due to a former needle biopsy.

Treatment of chronic osteomyelitis secondary to hydatid disease of bone using gentamycin beads

Hydatid disease of bone is rare. It remains asymptomatic over a long period. It is usually detected after a pathological fracture or secondary infection or following the onset of compressive myelopathy in cases of vertebral lesions. Secondary infection of hydatid disease of bone could be difficult to treat. The authors present a case of chronic osteomyelitis of the proximal aspect of the left femur in a 37-year-old male patient secondary to hydatid disease of bone. It was treated by aggressive debridement, gentamycin beads, and bone graft to fill the defect. No recurrence of the hydatid lesion or infection was detected after 2 years. This case showed that in addition to aggressive debridement, gentamycin beads may be valuable in eradicating the infection in such a case.

An unusual cause of knee pain in a young patient; hydatid disease of femur

INTRODUCTION

Osseous hydatid disease is a rare pathology and its differential diagnosis can be difficult.

PRESENTATION OF CASE

This article presents clinical and radiological findings of a femoral primary hydatid disease in a 23 year-old patient admitted with knee pain.

DISCUSSION

Osseous hydatid in femur is a rare entity. Curettage is one of the surgical options with high risk of anaphylaxis and implantation. Radical resection of involved segment is the preferred treatment method in the current literature. However, patient preference can be different.

CONCLUSION

Although late stages of this disease need be treated with amputation or disarticulation, in the early stages it can be treated with curettage and bone cementing. Our case with early diagnosis of hydatid disease of distal femur was treated successfully with curettage and bone cementing.

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.

Mucinous cystadenoma of the appendix misdiagnosed as cystic hydatid disease of the liver: a case report

Introduction

Primary neoplastic lesions presenting with a mucocele of the appendix are very rare and can be divided into benign variants of mucinous adenomas or cystadenomas, mucinous tumours of uncertain malignant potential or mucinous cystadenocarcinomas. Most of these tumourous mucoceles are asymptomatic and are found incidentally. The major complication of neoplastic mucinous appendiceal tumours is the development of a pseudomyxoma peritonei due to spreading of mucin-producing cells within the abdominal cavity.

Case presentation

A 44-year-old man presented with a history of non-specific symptoms of right upper abdominal pain. Abdominal ultrasound and computed tomography scan identified a cystic mass consistent with the morphological characteristics of an echinococcal hydatid cyst. After completing systemic albendazole therapy, an explorative laparotomy revealed a cystic tumour of the appendix. Ileocaecal resection was performed and pathology reports confirmed the diagnosis of a mucinous cystadenoma of the appendix. The postoperative course was uneventful.

Conclusion

Here we present the case of a man with a mucinous cystadenoma of the appendix mimicking cystic hydatid disease. We discuss the importance of re-evaluation and differential diagnostic reflections in cases of appendiceal mucocele.

Migrating and herniating hydatid cysts

OBJECTIVE

To present the prevalence and imaging findings of patients with hydatid disease (HD) showing features of migration or herniation of the hydatid cysts (HCs) and underline the clinical significance of this condition.

MATERIALS AND METHODS

Between May 2003 and June 2006, 212 patients with HD were diagnosed by abdomen and/or thorax CT, searched for migrating or herniating HC. Imaging findings of 7 patients (5 women, 2 men with an age range of 19-63 years; mean+/-S.D., 44+/-19 years) with HD showing transdiaphragmatic migration (6 subjects) or femoral herniation (1 subject) were evaluated. Diagnosis of all the patients were established by pathologic examination and migration or herniation was confirmed by surgery in all patients.

RESULTS

Liver HD were identified in 169 (79.7%) of 212 patients with HD. Transdiaphragmatic migration of HCs were identified in 6 (3.5%) of the 169 patients with liver HD. In one patient, femoral herniation of the retroperitoneal HC into the proximal anterior thigh was identified. All of these seven patients exhibiting migration or herniation of HCs had active HCs including 'daughter cysts'. Two patients had previous surgery because of liver HD and any supradiaphragmatic lesion was not noted before operation. Findings of migration or herniation were confirmed by surgery.

CONCLUSION

Active HCs may show migration or herniation due to pressure difference between the anatomic cavities, and in some of the patients, by contribution of gravity. Previous surgery may be a complementary factor for migration as seen in two of our patients. The possibility of migration or herniation in patients with HD should be considered before surgery.

Imaging of Parasitic Diseases of the Thorax

A broad spectrum of parasitic infections frequently affects the lungs, mediastinum, and thoracic wall, manifesting with abnormal imaging findings that often make diagnosis challenging. Although most of these infections result in nonspecific abnormalities, familiarity with their imaging features and the diagnostic pathways help the radiologist to formulate an adequate differential diagnosis and to guide diagnosticians in reaching a definitive diagnosis.

Osseous hydatid disease

Hydatid disease is still endemic in several regions worldwide and is caused in most cases by the larval form of two species of the tapeworm Echinococcus: E. granulosus and E. multilocularis. Bone involvement is rare (0.2-4%), affecting the spine in almost half of the cases. The disease is usually silent until a complication (e.g. paraplegia or pathologic fracture) occurs. Many cases are diagnosed intraoperatively. Pre-operative diagnosis is based on radiological findings and serological assays, which lack high sensitivity and specificity. A high index of suspicion is necessary for the diagnosis, especially in patients that live in or travel to sheep-raising areas where hydatid disease is endemic. The treatment of choice is surgical, following the principles of a locally malignant lesion. Chemotherapy (albendazole alone or in combination with praziquantel) is used as an adjuvant treatment or when surgery is not possible. The prognosis is often poor, especially in the spine: most patients do not recover neurologically, the mortality and complication rate is high and many cases recur, as it is often impossible to radically excise the pathologic tissue.

Diagnosis and percutaneous treatment of soft-tissue hydatid cysts

The purpose of this study is to demonstrate and discuss the radiological features of four patients with muscular hydatid disease and to evaluate the results of percutaneous treatment in these patients. Four patients (three female and one male) with six muscular hydatid cysts underwent percutaneous treatment and were followed up. The mean age of patients was 35 years (range: 12-60 years). Type I (n = 2), type II (n = 1), and type III (n = 3) hydatid cysts were observed in the thigh (n = 3) and gluteal (n = 1) region on radiologic examination. All interventions were performed under sonographic and fluoroscopic guidance. According to the type of the cyst, the procedure was carried out by either a "catheterization technique with hypertonic saline and alcohol" or a "modified catheterization technique." The mean cathaterization time was 13.7 days, ranging from 1 to 54 days. The dimensions of the residual cavity were noted at every sonographic control, and an average of 96.1% volume reduction was obtained in six cysts of four patients. No sign of viability was observed during the follow-up period. Cavity infection and cellulitis were observed as complications, which resolved after medical therapy. Percutaneous treatment is a safe and effective procedure in patients with soft-tissue hydatid cysts and should be considered as a serious alternative to surgery.

Alveolar hydatid disease of the liver: brief review and spectrum of adjacent organ invasion

The purpose of this study is to show the spectrum of adjacent organ invasion and to make a brief review of hepatic alveolar hydatid disease (AHD), using CT and MR imaging. We retrospectively reviewed CT and MR images of three patients with various adjacent organ invasions surgically and histologically proven to be AHD. Local invasion to right kidney and adrenal, right hemidiaphragm and lung were detected in one patient, right adrenal in another patient and gall bladder, duodenum, gastric wall and pancreas invasion in the other. AHD may rarely extend to the gall bladder, stomach, duodenum, pancreas, right adrenal and kidney, diaphragm, pleura and lung. The extension of the disease outside the liver is usually encountered in patients with large, peripherally located masses in the advanced stage of the disease.

Glenohumeral Joint Ganglion Cyst and Other Rare Cysts of the Axilla

Although ganglion cysts have been reported to arise from almost any joint, those arising from the glenohumeral joint producing an axillary mass are extremely rare. We report what we believe to be the eighth such case and describe its management. The unusual differential diagnosis and aids to diagnosis of axillary cysts are reviewed. Specific issues regarding axillary space ganglions are emphasized.

A rare cause of parotid swelling: Primary hydatid cyst

Hydatid disease is a zoonotic infection caused by Echinococcus species. Cystic form of this infection mostly involves liver and lung. Hydatid disease of the parotid gland is a very rare entity that may be easily overlooked in daily practice. On the other hand, rupture of the cyst during surgery may give rise to serious complications. We present a case of hydatid cyst of the parotid and discuss the differential diagnosis of this rare condition.

Hydatid disease of the tarsal bones. A case report

Hydatid disease is caused by the larval form of the tapeworm Echinococcus. Osseous cysts are rare and very few cases of foot infestation have been reported. We present the case of a 51-year-old woman who developed a palpable mass at the medial dorsal aspect of the right midfoot. Radiological examination showed cystic lesions in the cuneiforms and the navicular. The lesion was explored and several small cysts containing clear fluid were found. They were evacuated and the bone was curetted. The diagnosis of E. granulosus infestation was made histologically. After 15 years' follow-up there were no signs of recurrence. Osseous echinococcosis is a rare disease that may present as infective or neoplastic pathology. A high index of suspicion is necessary for its diagnosis, especially in patients who live in or travel to sheep-raising areas where hydatid disease is endemic.

Primary hydatid cyst in the anterior thigh: Sonographic findings

Hydatid cysts rarely involve the musculoskeletal system. We present the case of a 23-year-old man with a primary hydatid cyst between the femur and the quadriceps muscle in his left thigh. No cysts were located in the adjacent femur or quadriceps muscle. Cyst resection with sparing of the surrounding muscles, combined with anthelmintic therapy, was curative. In regions where hydatidosis is endemic, hydatid cysts should be included in the differential diagnosis of any unusual soft-tissue swelling.

Use of two sensitive and specific immunoblot markers, em70 and em90, for diagnosis of alveolar echinococcosis

Antibodies against Echinococcus multilocularis metacestodes were screened by immunoblotting sera from patients with alveolar echinococcosis (n = 39), cystic echinococcosis (n = 109), or other parasitic infections (n = 66) and healthy individuals (n = 32). Two antigens, approximately 70 and 90 kDa, are found to be valuable for confirmatory diagnosis, with a sensitivity and specificity of 100 and 99.51%, respectively.

Alveolar echinococcosis: MR findings in the liver

PURPOSE

To clarify the magnetic resonance (MR) imaging findings of alveolar echinococcosis in the liver.

MATERIALS AND METHODS

Thirty-five patients with 50 lesions histologically proven to be alveolar echinococcosis were evaluated with MR imaging. Lesions were assessed with regard to the distribution pattern of solid and cystic components and pattern of contrast material enhancement.

RESULTS

Cystic components exhibited two patterns at T2-weighted MR imaging: small round cysts and large and/or irregular cysts. Forty-eight lesions (96%) contained small round cysts. Twenty-six lesions (52%) had large and/or irregular cysts. Forty-five lesions (90%) were associated with a solid component. MR imaging characteristics were categorized into five types: multiple small round cysts without a solid component (two lesions [4%], type 1), multiple small round cysts with a solid component (20 lesions [40%], type 2), a solid component surrounding large and/or irregular cysts with multiple small rounds cysts (23 lesions [46%], type 3), a solid component without cysts (two lesions [4%], type 4), and a large cyst without a solid component (three lesions [6%], type 5). In most cases (97%), contrast enhancement was weak.

CONCLUSION

The MR findings of alveolar echinococcosis in the liver are multiple small round cysts with a weakly enhanced solid component. The cystic component can be a large and/or irregular lesion, and such lesions are depicted clearly at T2-weighted MR imaging.

Hydatid disease from head to toe

Hydatid disease (HD) is a unique parasitic disease that is endemic in many parts of the world. HD can occur almost anywhere in the body and demonstrates a variety of imaging features that vary according to growth stage, associated complications, and affected tissue. Radiologic findings range from purely cystic lesions to a completely solid appearance. Calcification is more common in HD of the liver, spleen, and kidney. HD can become quite large in compressible organs. Hydatid cysts (HCs) can be solitary or multiple. Chest radiography, ultrasonography (US), computed tomography (CT), magnetic resonance (MR) imaging, and even urography can depict HCs. The imaging method used depends on the involved organ and the growth stage of the cyst. US most clearly demonstrates the hydatid sands in purely cystic lesions, as well as floating membranes, daughter cysts, and vesicles. CT is best for detecting calcification and revealing the internal cystic structure posterior to calcification. MR imaging is especially helpful in detecting HCs of the central nervous system. Radiologic and serologic findings can generally help establish the diagnosis of HD, but an HC in an unusual location with atypical imaging findings may complicate the differential diagnosis. Nevertheless, familiarity with imaging findings, especially in patients living in endemic regions, is advantageous in this context.

Hydatid disease of bone: a mimic of other skeletal pathologies

Skeletal hydatidosis results from the deposition of the larval form of the Echinococcus, a genus of tapeworm. The incidence of bone disease is extremely low as most larvae are trapped by the liver and lung upon release of the embryo into the portal blood stream. The interpretation of imaging studies can prove very confusing because bone changes evolve with time, and the non-specificity of these findings often leads to a mistaken diagnosis. We present the case of a 35-year-old woman with long-standing pain in the left hip joint in which the findings on CT were thought of as being either tuberculous or neoplastic in nature. The result of a CT-guided biopsy and another done following surgery concurred on an unexpected diagnosis of a hydatid cyst. This case illustrates that in the absence of a high index of suspicion for echinococcal infection, the semblance of imaging findings of hydatid disease in bone to those of other skeletal pathologies can lead to misinterpretation.