Pulmonary hydatid infection
Pulmonary hydatid infection is a common manifestation of hydatid disease.
The lung is the second most common site of involvement with echinococcosis granulosus in adults after the liver (10-30% of cases), and the most common site in children1. The coexistence of liver and lung disease is present in only 6% of patients 2.
Thoracic involvement may occur via1:
- transdiaphragmatic route (0.6-16% of cases of hepatic disease)
- haematogenous spread
Although the echinococcosis granulosus presents commonly with unilocular cysts, echinococcosis multilocularis and echinococcosis vogeli may cause alveolar and polycystic echinococcosis.
Chest CT scan features include 2:
- multiple or solitary cystic lesion (most common)
- diameter of 1-20 cm
- unilateral or bilateral
- predominantly found in the lower lobes
Radiographic and CT features may differ in complicated and uncomplicated cysts.
Uncomplicated cysts are characterized by:
- round or oval masses with well-defined borders
- enhancement after contrast injection
- hypodense content relative to the capsule
Complicated cysts may show:
- meniscus sign or air crescent sign
- cumbo sign or onion peel sign
- water-lily sign
- consolidation adjacent to the cyst (ruptured cyst)
Other less common thoracic hydatid manifestations include: invasion of the mediastinum 4, pericardium, chest wall 5, cardiovascular system, or inferior vena cava 6.
- 1. Gottstein B, Reichen J. Hydatid lung disease (echinococcosis/hydatidosis). Clin. Chest Med. 2002;23 (2): 397-408, ix. - Pubmed citation
- 2. Polat P, Kantarci M, Alper F et-al. Hydatid disease from head to toe. Radiographics. 23 (2): 475-94. Radiographics (citation) - Pubmed citation
- 3. Pedrosa I, Saíz A, Arrazola J et-al. Hydatid disease: radiologic and pathologic features and complications. Radiographics. 20 (3): 795-817. Radiographics (citation) - Pubmed citation
- 4. Marcos FG, Popovsky S, Osorio ML. Hydatid cyst of the mediastinum. Dis Chest. 1969;56 (2): 160-2. - Pubmed citation
- 5. Ozdemir N, Akal M, Kutlay H et-al. Chest wall echinococcosis. Chest. 1994;105 (4): 1277-9. Chest (citation) - Pubmed citation
- 6. Franquet T, Plaza V, Llauger J et-al. Hydatid pulmonary embolism from a ruptured mediastinal cyst: high-resolution computed tomography, angiographic, and pathologic findings. J Thorac Imaging. 1999;14 (2): 138-41. - Pubmed citation