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 Table of Contents  
Year : 2017  |  Volume : 5  |  Issue : 1  |  Page : 129-130

Water lily sign and serpent sign in pulmonary hydatid cystic disease

Department of Pulmonary Medicine, ESIC Post Graduate Institute of Medical Science and Research, New Delhi, India

Date of Web Publication16-Jun-2017

Correspondence Address:
Ashish Ranjan
29 A, Ramesh Nagar, New Delhi - 110 015
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2321-4848.208184

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The teaching image depicts sections of CT chest showing water lily sign and serpent sign. In the diagnosis of pulmonary hydatid disease, these signs are pathognomonic, these must be corroborated clinically, and early interventions should be done to avoid rupture of cysts leading to complications.

Keywords: Hydatid cyst, pulmonary hydatid cyst, serpent sign, water lily sign

How to cite this article:
Ranjan A. Water lily sign and serpent sign in pulmonary hydatid cystic disease. Arch Med Health Sci 2017;5:129-30

How to cite this URL:
Ranjan A. Water lily sign and serpent sign in pulmonary hydatid cystic disease. Arch Med Health Sci [serial online] 2017 [cited 2022 Aug 17];5:129-30. Available from: https://www.amhsjournal.org/text.asp?2017/5/1/129/208184

A male patient aged 43 years presented with complaints of cough, expectoration, recurrent haemoptysisand weight loss. Amongst his diagnostic workup, the chest computed tomography (CT) showed classical features of bilateral pulmonary hydatid cysts. Surgical intervention was done and patient cured. Pulmonary involvement in the hydatid disease is common as lung is the second most common site for hematogenous spread,[1] but in children, lung is the most common site.[2] Liver and lungs simultaneously involved in about 6% of cases.[3] Cysts generally located in lower lobes (60% cases) and can be multiple (30% cases) and bilateral (20% cases).[4],[5] Hydatid disease is a parasitic infestation of humans caused by Echinococcus granulosus and multilocularis, which produce cystic lesions in any part of body. Hydatid cyst consists of three layers – the outermost pericyst made of fibrous tissue represents the response of the host to the parasite, middle layer of laminated membrane (ectocyst), and innermost layer of germinal epithelium (endocyst) which secretes the hydatid fluid internally and laminated membrane externally producing new generation of parasites. Sometimes, collapsed membranes of cyst may be seen floating on the surface of the cyst also known as the “water lily sign” [Figure 1].
Figure 1: Collapsed membranes of cyst floating on the surface of the cyst also known as the “water lily sign”

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Detachment of the endocyst with its collapse results into serpent sign [Figure 2]. The rupture may be related to decreasing intracystic pressure, degeneration, host response, trauma, or response to therapy.
Figure 2: Collapsed membranes of cyst floating on dependent portion of the cyst known as “serpent sign”

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Uncomplicated cysts appear as round, oval, or polycyclic well-defined mass lesions. In conclusion, CT is the imaging modality of choice which can provide an accurate diagnosis. There should be interdisciplinary awareness of the typical and atypical imaging features of the disease.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Beggs I. The radiology of hydatid disease. AJR Am J Roentgenol 1985;145:639-48.  Back to cited text no. 1
Pedrosa I, Saíz A, Arrazola J, Ferreirós J, Pedrosa CS. Hydatid disease: Radiologic and pathologic features and complications. Radiographics 2000;20:795-817  Back to cited text no. 2
Pomelov VS, Karimov ShI, Nishanov KhT. Surgical tactics in associated echinococcosis of the liver and lung. Khirurgiia (Mosk) 1991;11:69-74.  Back to cited text no. 3
Polat P, Kantarci M, Alper F, Suma S, Koruyucu MB, Okur A. Hydatid disease from head to toe. Radiographics 2003;23:475-94; quiz 536-7.  Back to cited text no. 4
Aytac A, Yurdakul Y, Ikizler C, Olga R, Saylam A. Pulmonary hydatid disease: Report of 100 patients. Ann Thorac Surg 1977;23:145-51.  Back to cited text no. 5


  [Figure 1], [Figure 2]


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