Hepato-pulmonary hydatidosis

Clinical History

A 63-year-old woman, non-smoker, with unremarkable history, appeared with two-week symptoms consisting of fever, cough, expectoration, haemoptysis and general malaise. Biochemical analysis showed leukocytosis and eosinophilia, as well as elevation of transaminase.

Imaging Findings

At the emergency room a chest radiograph showed a right lower lobe well-defined opacity (Fig. 1a). On the lateral view the opacity was limited anteriorly by the major fissure and inferiorly by the diaphragm (Fig. 1b).
Computed tomography (CT) revealed a low attenuated (<20UH) well-defined mass, with irregular borders, in the right lower lobe with peripheral enhancement (Fig. 2). On the abdominal CT two well-defined cystic masses were identified. The right lobe cyst was a homogeneous hypoattenuated (<20UH) lesion with a peripheral calcified capsule (Fig. 3a) and the left one had a heterogeneous content, with hyperdense internal membranes (Fig. 3b). Coronal CT reconstruction supported the similar appearance of thoracic and abdominal lesions (Fig. 4).

Discussion

Hydatid disease (HD) is a parasitic zoonosis acquired by humans secondary to the ingestion of food contaminated with Echinococcus granulosus eggs or by direct contact with contaminated dogs [1]. In Europe HD is uncommon and usually seen in immigrants or after traveling to endemic areas [2]. The ingested embryos (oncospheres) pass through the duodenal mucosa to the portal vein where they are captured by the hepatic capillaries; here they may die or grow into hepatic cysts (HCs). Some of the oncospheres may escape from the hepatic capillaries and infect distant organs [2].

The most frequently affected organs are the liver and the lungs; the spleen, brain, retroperitoneum, kidneys, heart, muscles and skeleton are involved less commonly. Lungs are the most frequently affected organ in children [3]. The coexistence of hepatic and pulmonary disease occurs only in 6% of patients [2].

HD is often asymptomatic, but large lung cysts may develop symptomatology such as irritating cough and haemoptysis; liver cysts can obstruct bile ducts causing jaundice [1]. Radiological signs are important because of the varied symptomatology and Echinococcus serology is positive only in 25% of infected patients on initial stages [1].

Hepatic cysts may have different imaging findings; from simple cysts to solid-appearing pseudotumours. HCs can be solitary or multiple and are located most frequently in the right hepatic lobe. Cysts may show a thick capsule, wavy internal bands or septa representing delaminated endocyst or present daughter cysts. Peripheral focal areas of calcification are present in up to 50% of cases [2]. On MRI the cystic wall is hypointense on T1- and T2-weighted images (WI). The cyst content appears hypointense on T1-WI, with marked hyperintensity on T2-WI; daughter cysts are hypointense or isointense relative to the cyst content on T1- and T2-WI [1, 2]. The walls and the cyst internal septal enhance after intravenous contrast administration.

Lung infection occurs by trans-diaphragmatic migration of a hepatic cyst or by haematogenous route. Imaging features include a well-defined solitary cystic lesion, or less frequently multiple lesions, found mainly in the lower lobes. Cyst may change in shape according to the adjacent structures. Computed tomography shows a cystic lesion with hypodense content and a thick capsule that enhances after contrast administration [3].

HD complications include cyst rupture, which occurs in up to 50-90%, and bacterial superinfection. Indicated treatment is Albendazol but larger cysts may require surgical resection in combination with Albendazol [4].

Differential Diagnosis List

Final Diagnosis

Hepatic-pulmonary hydatidosis

URL:	https://eurorad.org/case/12349
DOI:	10.1594/EURORAD/CASE.12349
ISSN:	1563-4086