1. Echinococoza

5. Foxes may be a reservoir of zoonotic agents such as rabies virus and the parasite Echinococcus multilocularis.

6. Hydatid disease. Cyst revealed on CT scan (left) and at craniotomy (right).

7. Echinococcosis. Cerebral angiography showing displacement of vessels by a large mass in the frontal region.

9. Hydatid disease. Surgical specimen swowing multiple thin-walled, fluid/ filled cysts.

10. Echinococcosis. Cyst removed from patient.

11. A large, thick-walled unilocular cyst is characteristic of infestation of Echinococcus granulosus.

12. Hidatid disease. Chest radiographs showing well-defined round lesion in middle zone of right lung.

13. Hydatid disease. Chest radiograph snowing partially evacueted cyst (arrowed) in the middle yone of the right lung.

14. Echinococcus cyst in right lung of an adult male.

15. Fluid-filled echinococcus cyst in the lungs of an adolescent male.

16. Hydatid disease. CT scan of the thorax showing hydatid cyst of right lung.

17. Gross pathology photograph of the membrane and hydatid daughter cysts excised from a human lung. Hydatid disease is a parasitic infestation by a tapeworm of the genus Echinococcus. Endemic areas usually involve third world countries. The liver is the most common organ involved, followed by the lungs.

18. Echinococcus abscess of liver in an adult, the most common site of abscess formation.

19. Cysts are fused in the liver parenchyma. E
Cysts are fused in the liver parenchyma. E. multilocularis is endemic in Hokkaido.

20. Echinococcosis. An echinococcal cyst showing daughter cyst, rescted from the liver (left), and histological section showing the layers of an hydatid cyst (right).

21. Gross cross-section of liver with a hydatid (echinococcal) cyst
Gross cross-section of liver with a hydatid (echinococcal) cyst. The cyst consists of a large unilocular cyst with daughter cysts.

22. Echinococcus cyst in the right lobe of the liver in a 27-year-old male
Echinococcus cyst in the right lobe of the liver in a 27-year-old male. Note the striking elevation of the right hemidiaphragm.

23. Abdominal radiograph showing hepatic mass (echinococcus cyst).

24. Echinococcosis. Abdominal radiograph showing a calcified hydatid cyst in the liver.

25. Liver cyst due to echinococcus granulosus infection
Liver cyst due to echinococcus granulosus infection. Computed tomography scan demonstrates a large multilocular cystic mass in the liver with distinctive internal daughter cysts characteristic of Echinococcus infection. Approximately 40% of echinococcal (hydatid) cysts will demonstrate some crescentic or curvilinear calcification.

26. Hydatid disease. Computerized tomogram showing ruptured cyst with internal membrane floating within cavity.

27. Echinococcosis. Ultrasound scan showing multioculated cyst in liver.

28. Echinococcosis. CT scan showing large multioculated cyst in left lobe of liver.

29. Echinococcosis. Endoscopic retrograde cholangio-pancreatography showing intrahepatic hydatid cystic space draining into the biliary tree.

30. Echinococcus granulosus
Echinococcus granulosus. Daughter cysts within a large unilocular cyst, surgically removed from a Peruvian Nisei. The patient died of anaphylactic shock during surgery. Leakage of the cyst fluid (hydatid fluid) should be avoided.

31. Echinococcosis. (a) scolices of E
Echinococcosis. (a) scolices of E. granulosus (b) hooklet at a higher magnification.

32. Protoscolex in the daughter cyst (stereo microscopic observation)
Protoscolex in the daughter cyst (stereo microscopic observation). Hooklets on the rostellum are characteristic. In old cysts, isolated protoscolexes accumulate as hydatid sand.

33. "Hydatid sand".  Fluid aspirated from a hydatid cyst will shows multiple protoscolices (size approximately 100 µm), each of which has typical hooklets.

34. Echinococcus granulosus
Echinococcus granulosus. Scolices from a hydatid cyst showing both invaginated and evaginated hooklets and suckers.

35. The scolex is invaginated and has a double row of hooklets.
Scolex of Echinococcus granulosus.
The scolex is invaginated and has a double row of hooklets.

36. Echinococcus granulosus. Adult tapeworm.

37. Echinococcosis. Cyst inliver showing laminated, non nuclear layer, nucleated germinal layer with many brood capsules attached, and multiple scolices within the cyst cavity.

38. Beautiful lamellated structure is demonstrated in the cyst wall by PAS stain.

39. Section
of a hydatid (echinococcal) cyst wall displaying a laminated membrane and germinal layer.

40. Hooklet or “scimitar” from Echinococcus granulosus showing acid-fast positivity.

41. Echinococcosis. Fluid from cyst viewed under polarized light showing hook of hydatid.