Hydatid Disease: Radiologic and Pathologic Features and Complications

Abstract

Hydatid disease primarily affects the liver and typically demonstrates characteristic imaging findings. However, there are many potential local complications (eg, intrahepatic complications, exophytic growth, transdiaphragmatic thoracic involvement, perforation into hollow viscera, peritoneal seeding, biliary communication, portal vein involvement, abdominal wall invasion). Furthermore, secondary involvement due to hematogenous dissemination may be seen in almost any anatomic location (eg, lung, kidney, spleen, bone, brain). Ultrasonography (US) is particularly useful for the detection of cystic membranes, septa, and hydatid sand. Computed tomography (CT) best demonstrates cyst wall calcification and cyst infection. CT and magnetic resonance (MR) imaging may demonstrate cyst wall defects as well as the passage of contents through a defect. Chest radiography, US, CT, and MR imaging are all useful in depicting transdiaphragmatic migration of hydatid disease. CT is the modality of choice in peritoneal seeding. US and CT demonstrate rupture in most cases that involve wide communication. Indirect signs of biliary communication include increased echogenicity at US and fluid levels and signal intensity changes at MR imaging. CT allows precise assessment of osseous lesions, whereas MR imaging is superior in demonstrating neural involvement. Familiarity with atypical manifestations of hydatid disease may be helpful in making a prompt, accurate diagnosis.

Pericardial hydatid cyst presenting with cardiac tamponade

“…Diagnosis is based on cardiac imaging techniques, such as echocardiography, computed tomography scans, magnetic resonance imaging and serological tests (2). Echocardiography is the diagnostic tool of choice because it is noninvasive, easily performed, and has a high sensitivity in the determination of intracardiac hydatid cysts and in planning surgical intervention (4,7,8).…”

“…On ultrasonography, the appearance of a round, thinwalled, multiloculated mass is characteristic of the echinococcal cyst (2). A hydatid cyst should always be considered when there is an intracardiac cystic image.…”

“…A hydatid cyst should always be considered when there is an intracardiac cystic image. But, the echolucent and multiseptate nature of hydatid cysts may sometimes be absent, and they may appear as a tumour-like mass (2,9). The recommended treatment is excision of the cyst because of the possibility of severe complications, including cyst rupture and sudden death, even in asymptomatic patients (6,7,10).…”

“…People are infected with the intermediate stage of the parasite by ingesting water or food contaminated with eggs or by direct contact with infected dogs. Once the parasite passes through the intestinal wall to reach the portal venous system or lymphatic system, the liver acts as the first line of defense and is therefore the most frequently involved organ (1,2). In people, hydatid disease involves the liver in approximately 75%, the lung in 15% and other anatomical locations in 10% of cases (2).…”

Case Report: Cardiac Hydatid Cyst

“…The main route of acquiring the infection is through the ingestion of food or fluids that contaminated with egg-containing feces. The embryo of the parasite is released into the intestinal tract and carried to the liver by the portal circulation [2]. The most common organ involved is the liver (50% to 70%) and the lung (20% to 30% of cases) in humans [3].…”