DiFFUerent Locations of Hydatid Cysts

Abstract

Hydatid disease is a parasitosis caused by Echinococcus granulosus1 and an important health problem worldwide.2 Incidental human infestation with larval form resultsinformation of hydatid cysts in various parts of the body, the liver being the most common site.3 Peritoneal cavity, spleen, kidney, spinal column, retroperitoneal space, abdominal wall, myocardium, and the thoracic wall are unusually involved.4 CASE REPORTS We report our experience with hydatid cysts located in many unusual locations. The study duration was 2 years. Clinical features and investigation and management details of the patients are shown in Table 1. In all patients, diagnosis was confirmed after surgical excision by histopathology. Patients were further investigated in details, and it showed no evidence of other visceral lesions except incase 8. Because of lack of facilities, serological tests could not beperformed. This patient also had evidence of local infection. All patients received a course of albendazole starting before surgery andcontinued in the postoperative period for a total of 3 weeks forthe primary management and to prevent recurrence. Patients were followed up clinically and if necessary with imaging, particularly ultrasound.TABLE 1: Clinical Details of the PatientsFIGURE 1: Cranial CT scan revealing a primary cerebral hydatid cyst appearing as a left frontoparietal hypointense, cystic, well-demarcated lesion.FIGURE 2: Hydatid cyst of left parietal lobe, intraoperative photograph.FIGURE 3: Preoperative photograph hydatid cyst in axilla (left), high-frequency USG showing hydatid cyst in the axillary region (right).FIGURE 4: Intraoperative photograph of a hydatid cyst in the axilla.FIGURE 5: Intraoperative photograph of delivery of membrane from a hydatid cyst over the anterior abdominal wall.FIGURE 6: CT scan of the abdomen showing a hydatid cyst in the liver.FIGURE 7: CT scan abdomen showing a hydatid cyst in the gallbladder.FIGURE 8: MRI showing floating membrane of the left renal hydatid cyst.FIGURE 9: Delivery of hydatid membrane (left), part of a pericyst that is adherent to the lower pole of the left kidney (right).FIGURE 10: CT scan of the abdomen showing a retroperitoneal hydatid cyst.FIGURE 11: Intraoperative photograph of delivery of a hydatid cyst along with the pericyst.FIGURE 12: Preoperative photograph of an infected hydatid cyst of the thigh.FIGURE 13: MRI film showing hydatid cyst in the thigh muscle region.FIGURE 14: Ultrasound showing hydatid cyst in the thigh muscle region.FIGURE 15: Intraoperative photograph showing daughter cysts.DISCUSSION Cerebral Hydatid Cysts Cerebral hydatid cysts are extremely rare, forming 2% of all intracranial space-occupying lesions even in counties where the disease is endemic.5 Cerebral hydatid cyst diagnosis is usually based on a pathognomonic computed tomography (CT) pattern.5 The treatment of intracranial hydatid cysts is essentially surgical, especially in patients with raised intracranial pressure or deficits.6-8 Intraoperative ultrasound guidance is a useful adjuvant for surgery of intracranial cysticlesions.9 Axilla The axilla is a rare location for hydatid cysts to occur, and only a few case reports are there in literature.10-12 Excision of the cystic mass is the definitive therapy, and histopathology will confirm the diagnosis. Although the combination of albendazole and praziquantel seems to be the most eFFUective medical treatment, it is not an alternative tosurgery.10 Liver The liver acts as a filter for hydatid larvae, making it the most commonly aFFUected organ.13-15 The right lobe of theliver is aFFUected in 80% of cases, and the left lobe in 20%.14,15 Up to one third of patients with liver hydatid can develop complications such as rupture (into the biliary tree, thorax, or peritoneum), secondary infection, anaphylactic shock, sepsis, and liver replacement.13-15 Gallbladder Gallbladder hydatid cysts are rare, and the mode of entry is via the cystic duct from the liver, where the cysts undergo maturation.16-19 Gallbladder is usually involved as aresult of either intrabiliary rupture of a hepatic hydatid cyst or of a direct cyst rupture into the gallbladder.17 A primary hydatid cyst of the gallbladder is even a more uncommon andrarer disease.18,20 These cysts have an annular pattern on ultrasonography (USG).21 That is described as "cyst within acyst."22 Anterior Abdominal Wall Involvement of the anterior abdominal wall is an extremely rare presentation of hydatid cyst.23,24 Total excisionfollowed by chemotherapy with albendazole gives excellent results.23,24 Correct surgical management, including the intraoperative avoidance of spillage of cyst fluid, demands preoperative diagnosis or at least a high index of suspicion.23 Renal Location Isolated hydatid disease of the kidney is a rare condition that can be challenging to diagnose.25-27 Renal hydatid disease can cause obstruction of the ureteropelvic junction, resulting in hydronephrosis and complete destruction of the renal parenchyma.25,27 The diagnosis can be made by USG, CT scan, and, in some diFFUicult cases, magnetic resonance imaging (MRI). We reported a case of a renal hydatid cyst ina 47-year-old man mimicking at imaging, even at MRI, a hypovascular renal tumor.26 Surgical excisions without spillage of the cyst content is the mainstay ofthe treatment.25-27 Retroperitoneum Hydatid disease of the retroperitoneum is also a very rare condition.28-30 Clinical features include flank pain, abdominal mass, and nonspecific symptoms such as nausea and vomiting.30 A primary hydatid cyst of the retroperitoneum is a distinct clinical entity that must be considered when caring for a patient with a retroperitoneal mass in endemic regions. It should be treated after the diagnosis is confirmed without any delay because of secondary spillages due to perforations and other possible complications.31 Thigh Isolated primary hydatid disease of the skeletal muscle is rare because the parasite has to cross the pulmonary and hepatic barriers to reach the muscles.32,33 The high lactic acid level in muscle tissue is considered unfavorable for parasitesurvival.34 Moreover, muscular contractions prevent fixation of larvae to the tissue.34 Primary hydatid disease of the skeletal muscle without systemic involvement is rare.35-39 Ultrasonography should be the first diagnostic tool used for detection of hydatid disease of soft tissue. However, MRI isbest for clear identification of involved structures and for surgical planning.40,41 En bloc resection alone is curative forintramuscular hydatid disease.33,42 Surgery should be followed by adjunctive chemotherapy to eliminate any possible larvae disseminated. Infection in the hydatid cyst of the thighhas rarely been reported. For infected hydatid cyst (our case 8), there is no eFFUective medical treatment except surgerysupplement with systemic antibiotics and chemotherapy.37 CONCLUSION Hydatid disease can aFFUect any organ or area throughout the body, and suspicion of this disease should be justified in patients presenting with a cystic mass in endemic areas.43 The best therapeutic option of hydatid cysts is complete surgical excision without spillage of the contents. However, medical therapy with mebendazole or albendazole is recommended to sterilize the cyst, decrease the chance of anaphylaxis, decrease the tension in the cyst wall, and reduce the recurrence rate postoperatively.44 A high index of suspicion is needed for preoperative diagnosis of hydatid disease in unusual locations, and it should be considered in the diFFUerential diagnosis for any cystic soft tissue mass found in patients from areas where the disease is endemic.