Giant isolated hydatid lung cyst: two case reports

Abstract

Background: Echinococcosis is a parasitic disease caused by Echinococcus granulosus and causes cystic lesions in the liver and lungs commonly. It is endemic in many parts of the world, and though humans are incidental hosts of the parasite, the disease can have severe consequences.

Case presentation: We present two patients from pastoralist (Maasai) communities in rural Tanzania with long-standing chest pain accompanied by hemoptysis. Both were managed surgically after diagnosis, but one patient died of the complications following rapture of the cyst during surgery. Histopathological evaluation of the specimens confirmed the diagnosis of giant hydatid cysts.

Conclusion: Animal-keeping communities such as the Maasai are at risk of echinococcosis because of their close proximity to animals. The diagnosis can be made on the basis of history and radiological as well as laboratory findings. Surgery is a recommended mode of treatment, though it carries a high risk, especially when the cyst ruptures. Primary preventive measures are thus necessary in order to avoid the secondary and tertiary complications of the management of giant hydatid cysts, which is difficult in resource-limited endemic areas.

Keywords: Echinococcus; Hydatid cyst; Pulmonary; Tanzania; Zoonoses.

Fig. 1

Ruptured cyst attached to lung parenchyma

Fig. 2

a Bilayered daughter cysts developing in large mother cysts and scolices. The worm produces sediment, so-called hydatid sand (Hematoxylin & eosin (H&E) staining; × 10 original magnification). b Lung sections with mixed chronic inflammation consisting mononuclear cells, eosinophils, and multinucleated giant cells. (H&E staining; × 20 original magnification)

Fig. 3

Chest x-ray posteroanterior view shows a large, rounded opacity in the right hemithorax causing mediastinal shift toward the contralateral side. Left-sided tracheal shift is seen with right main bronchus compression. No rib destruction is visualized. Features are suggestive of a hydatid cyst

Fig. 4

Contrast-enhanced chest computed tomography in axial, coronal, and sagittal views demonstrating a large cystic lesion in the right upper and middle hemithorax measuring 15.5 cm (AP) × 11.3 cm (T) × 14.9 cm (CC) and displacing the mediastinum to the contralateral side of the chest. The cystic lesion has a thick rind with double membranes on its anterior and posterior walls. No internal architecture or daughter cysts are seen. Features are suggestive of hydatid cyst. AP Antero-posterior, T Transverse, CC Craniocaudal

Fig. 5

Cyst attached to lung parenchyma

Fig. 6

a The cyst comprises three layers: The outermost pericyst is fibrous; the middle ectocyst layer is laminated, hyaline, and acellular; and the inner endocyst is the germinative layer, which consists of daughter cysts and brood capsules with scolices. b The chronic granulomatous inflammation reaction