Lung - nontumor
Infections
Echinococcal cyst of lung

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 24 February 2017, last major update September 2011

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed search: echinococcal [title] cyst pulmonary

Cite this page: Echinococcal cyst of lung. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungnontumorechinococcal.html. Accessed May 25th, 2017.
Clinical features
  • Also called hydatid cyst
  • Humans become infected by eating food contaminated with tapeworm eggs, becoming intermediate hosts
  • Eggs from dog tapeworm Echinococcus granulosus or E. multilocularis where foxes are the most common definitive hosts; other species rarely cause hydatid diseae in humans
  • For E. granulosus, sheep are most important intermediate hosts; for E. multilocularis, rodents are most important intermediate hosts
  • E. granulosus is more common in humans and is most common cestode infection of the lung
  • Eggs hatch in duodenum and spread to liver, lung, bone or elsewhere
  • E. granulosus cysts are most common in liver, 5% - 15% occur in lung; pulmonary disease is often secondary to hepatic disease (World J Surg 2001;25:46)
  • Larvae lodge in capillaries and incite a mononuclear and eosinophilic inflammatory cell response
  • Many larvae die, some encyst
  • Pulmonary cysts may be asymptomatic or cause respiratory compromise by compressing airways or lung parenchyma; rarely complicated by Aspergilloma (Br J Radiol 2008;81:e279)
  • Cyst rupture may cause fatal anaphylactic shock or pneumonia with consequent development of numerous new cysts throughout lung
Case reports
Microscopic (histologic) description
  • Cysts gradually enlarge and years later may be several centimeters in diameter
  • Cyst is bilayered and surrounded by fibroblasts, mononuclear cells, eosinophils, multinucleated giant cells
  • Daughter cysts usually develop in large mother cyst
  • Daughter cysts develop as projections from a germinative layer and form brood capsules
  • Degenerating scolices of developing worms produce sediment, so called "hydatid sand"
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Dr. Hanni Gulwani, New Delhi (India)

Cytology images

Images hosted on other servers:

2 cm lung nodule

BAL fluid - scolices