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Hydatid disease involving some rare locations in the body: a pictorial essay.

Yuksel M, Demirpolat G, Sever A, Bakaris S, Bulbuloglu E, Elmas N - Korean J Radiol (2007 Nov-Dec)

Bottom Line: Unusual sites for this disease can cause diagnostic problems.This pictorial essay illustrates various radiological findings of HD in the liver, spleen, kidney, pancreas, peritoneal cavity, omentum, adrenal, ovary, lung, mediastinum and retroperitoneum.Familiarity with the imaging findings of HD may be helpful in making an accurate diagnosis and preventing potential complications.

View Article: PubMed Central - PubMed

Affiliation: KSU Medical School, Department of Radiology, Kahramanmaras, Turkey. myuksel@ksu.edu.tr

ABSTRACT
Hydatid disease (HD) is an endemic illness in many countries, and it poses an important public health problem that's influenced by peoples' socioeconomic status and migration that spreads this disease. Although rare, it may occur in any organ or tissue. The most common site is the liver (59-75%), followed in frequency by lung (27%), kidney (3%), bone (1-4%) and brain (1-2%). Other sites such as the heart, spleen, pancreas and muscles are very rarely affected. Unusual sites for this disease can cause diagnostic problems. This pictorial essay illustrates various radiological findings of HD in the liver, spleen, kidney, pancreas, peritoneal cavity, omentum, adrenal, ovary, lung, mediastinum and retroperitoneum. Familiarity with the imaging findings of HD may be helpful in making an accurate diagnosis and preventing potential complications.

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Rupture of hydatid cyst into the biliary tree in a 54-year-old woman.A, B. The axial MR image of the upper abdomen using a fast spin-echo T2-weighted sequence shows a hyperintense cystic lesion (short white arrow), including hypointense linear structures representing detached membranes, in the right lobe of liver. There is the hypointense rim (black arrowhead) at the periphery of the lesion. MRI reveals cyst wall defect (black arrow) and the passage of detached membranes through a defect into the extrahepatic bile duct (white arrowhead). Note the biliary dilatation (long white arrows) due to obstruction of the extrahepatic bile duct by hydatid membranes.
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Figure 10: Rupture of hydatid cyst into the biliary tree in a 54-year-old woman.A, B. The axial MR image of the upper abdomen using a fast spin-echo T2-weighted sequence shows a hyperintense cystic lesion (short white arrow), including hypointense linear structures representing detached membranes, in the right lobe of liver. There is the hypointense rim (black arrowhead) at the periphery of the lesion. MRI reveals cyst wall defect (black arrow) and the passage of detached membranes through a defect into the extrahepatic bile duct (white arrowhead). Note the biliary dilatation (long white arrows) due to obstruction of the extrahepatic bile duct by hydatid membranes.

Mentions: The liver is the most common site of HC. The cysts may cause pain, discomfort, abdominal swelling or a palpable mass or thrill (5, 6). In the early stages of the disease, the appearance of HCs may be uncharacteristic and mimic that of simple cysts. However, the double-line sign can often be seen on sonography in unruptured HCs (Fig. 5) (3, 4). Simple liver cysts do not demonstrate internal structures (2, 3), although multiple echogenic foci due to hydatid sand may be seen within the lesion by repositioning the patient on sonography (Fig. 6) (5). On MRI, a low-signal-intensity rim can be helpful to differentiate a unilocular HC from a simple liver cyst (2). Multiple unilocular cysts are indistinguishable from polycystic disease (2, 5). When echinococcal cysts become enlarged, they can produce pericystic biliary tract dilatation due to the mass effect (Fig. 7) (2, 5, 9). Decreasing intracystic pressure, endocyst degeneration, host response, trauma and medical treatment can cause separation of the endocyst from the pericyst (2, 3). Complete collapse of the endocyst results in a sonographic water-lily sign when the parasite lies in the most dependent part of the cyst or this produces an irregular, solid echo pattern (Fig. 8) (5). The wall of HC, even without calcification, is typically seen as a high-attenuated structure on unenhanced CT (Fig. 1) (3). The calcification may occur in the cyst wall or internally in the cyst, and this is detected on radiography in 20% to 30% of liver HCs (Fig. 3) (2, 3, 5). Following the formation of HC, many potential local complications may develop such as rupture, infection (Fig. 9), perforation to the biliary tree (up to 90% of HCs) (Fig. 10), and involvement of the portal venous system (Fig. 11), diaphragm and thoracic cavity (0.6%-16% of the cases with hepatic HCs) (2, 3).


Hydatid disease involving some rare locations in the body: a pictorial essay.

Yuksel M, Demirpolat G, Sever A, Bakaris S, Bulbuloglu E, Elmas N - Korean J Radiol (2007 Nov-Dec)

Rupture of hydatid cyst into the biliary tree in a 54-year-old woman.A, B. The axial MR image of the upper abdomen using a fast spin-echo T2-weighted sequence shows a hyperintense cystic lesion (short white arrow), including hypointense linear structures representing detached membranes, in the right lobe of liver. There is the hypointense rim (black arrowhead) at the periphery of the lesion. MRI reveals cyst wall defect (black arrow) and the passage of detached membranes through a defect into the extrahepatic bile duct (white arrowhead). Note the biliary dilatation (long white arrows) due to obstruction of the extrahepatic bile duct by hydatid membranes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2627456&req=5

Figure 10: Rupture of hydatid cyst into the biliary tree in a 54-year-old woman.A, B. The axial MR image of the upper abdomen using a fast spin-echo T2-weighted sequence shows a hyperintense cystic lesion (short white arrow), including hypointense linear structures representing detached membranes, in the right lobe of liver. There is the hypointense rim (black arrowhead) at the periphery of the lesion. MRI reveals cyst wall defect (black arrow) and the passage of detached membranes through a defect into the extrahepatic bile duct (white arrowhead). Note the biliary dilatation (long white arrows) due to obstruction of the extrahepatic bile duct by hydatid membranes.
Mentions: The liver is the most common site of HC. The cysts may cause pain, discomfort, abdominal swelling or a palpable mass or thrill (5, 6). In the early stages of the disease, the appearance of HCs may be uncharacteristic and mimic that of simple cysts. However, the double-line sign can often be seen on sonography in unruptured HCs (Fig. 5) (3, 4). Simple liver cysts do not demonstrate internal structures (2, 3), although multiple echogenic foci due to hydatid sand may be seen within the lesion by repositioning the patient on sonography (Fig. 6) (5). On MRI, a low-signal-intensity rim can be helpful to differentiate a unilocular HC from a simple liver cyst (2). Multiple unilocular cysts are indistinguishable from polycystic disease (2, 5). When echinococcal cysts become enlarged, they can produce pericystic biliary tract dilatation due to the mass effect (Fig. 7) (2, 5, 9). Decreasing intracystic pressure, endocyst degeneration, host response, trauma and medical treatment can cause separation of the endocyst from the pericyst (2, 3). Complete collapse of the endocyst results in a sonographic water-lily sign when the parasite lies in the most dependent part of the cyst or this produces an irregular, solid echo pattern (Fig. 8) (5). The wall of HC, even without calcification, is typically seen as a high-attenuated structure on unenhanced CT (Fig. 1) (3). The calcification may occur in the cyst wall or internally in the cyst, and this is detected on radiography in 20% to 30% of liver HCs (Fig. 3) (2, 3, 5). Following the formation of HC, many potential local complications may develop such as rupture, infection (Fig. 9), perforation to the biliary tree (up to 90% of HCs) (Fig. 10), and involvement of the portal venous system (Fig. 11), diaphragm and thoracic cavity (0.6%-16% of the cases with hepatic HCs) (2, 3).

Bottom Line: Unusual sites for this disease can cause diagnostic problems.This pictorial essay illustrates various radiological findings of HD in the liver, spleen, kidney, pancreas, peritoneal cavity, omentum, adrenal, ovary, lung, mediastinum and retroperitoneum.Familiarity with the imaging findings of HD may be helpful in making an accurate diagnosis and preventing potential complications.

View Article: PubMed Central - PubMed

Affiliation: KSU Medical School, Department of Radiology, Kahramanmaras, Turkey. myuksel@ksu.edu.tr

ABSTRACT
Hydatid disease (HD) is an endemic illness in many countries, and it poses an important public health problem that's influenced by peoples' socioeconomic status and migration that spreads this disease. Although rare, it may occur in any organ or tissue. The most common site is the liver (59-75%), followed in frequency by lung (27%), kidney (3%), bone (1-4%) and brain (1-2%). Other sites such as the heart, spleen, pancreas and muscles are very rarely affected. Unusual sites for this disease can cause diagnostic problems. This pictorial essay illustrates various radiological findings of HD in the liver, spleen, kidney, pancreas, peritoneal cavity, omentum, adrenal, ovary, lung, mediastinum and retroperitoneum. Familiarity with the imaging findings of HD may be helpful in making an accurate diagnosis and preventing potential complications.

Show MeSH
Related in: MedlinePlus