Asian Cardiovasc Thorac Ann 2004;12:257-259
© 2004 Asia Publishing EXchange Ltd
Atypical Pulmonary Giant Hydatid Cyst as Bilaterally Symmetrical Solitary Cysts
Saadia Rashid, MD,
Saulat Hasnain Fatimi, MD
Department of Surgery, The Aga Khan University, Karachi, Pakistan
For reprint information contact: Saadia Rashid, MD Tel: 1 905 791 7566 Email: saadia_rashid{at}hotmail.com 116 Avondale Blvd, Brampton, Ontario L6T 1H7, Canada.
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ABSTRACT
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A pulmonary giant hydatid cyst, a special clinical entity, is rare. Our case involves a young patient who presented with a bilaterally symmetrical solitary cyst in each lung, a feature consistent with congenital lung cysts. The radiological and immunological findings were equivocal. A diagnosis of giant hydatid cyst was made intraoperatively and both cysts were removed conservatively. A follow-up showed complete recovery.
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INTRODUCTION
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A hydatid cyst is a parasitic infection caused by Echinococcus Granulosus, characterized by the formation of cysts in the liver, lungs and rarely in other parts of the body. Pulmonary hydatid cyst presents either as a solitary lung cyst or as multiple cysts in one or more lobes of one or both lungs. According to a study done by Burgos and colleagues, the former accounts for around 70% and the latter accounts for 30%.1 Large cysts in the lungs is a special clinical entity termed as giant hydatid cysts.2 There is no universally accepted size to define a pulmonary hydatid cyst as "giant", but in an endemic country, the size can increase up to two thirds of a hemithorax.3 Yet a 6 cm hydatid cyst is rare.4 The cases reported so far in literature present as a unilateral solitary giant hydatid cyst.2,4
We discuss a case of an unusual presentation of giant hydatid cysts as a solitary cyst in each lung giving a striking bilaterally symmetrical picture, a feature more consistent with congenital lung cysts. To date, no such case of giant hydatid lung cyst has been reported in literature.
A previously healthy 12-year-old girl from Afghanistan without any previous history of lung disease, presented with complaints of bilateral chest pain, shortness of breath, cough and a low grade fever for the past eight months. Her cough was persistent, producing a small amount of white sputum but with no hemoptysis. She also complained of weight loss and decreased appetite.
Upon physical examination, she weighed 18 kg and her height was 124 cm. Her vital signs were normal. However, her oxygen saturation reduced to 96% in room air. A chest examination revealed bilateral crepitations and reduced air entry in the middle and lower zones on both sides of the lungs which were dull on percussion. An examination of other systems was normal. Laboratory investigations showed eosinophilia (55%) and a raised ESR (55 mm in the 1st hour).
The chest X-Ray showed a well defined, smoothly outlined, oval shape soft tissue, opaque in density occupying the lower two-thirds of each lung, giving a bilaterally symmetrical picture (Figure 1
). The hilum was also seen. The cardiac silhouette and bony cage were intact. These findings were equivocal for both congenital cysts and giant hydatid cysts of the lung of an uncomplicated variety (uncomplicated as defined by Halezeroglu and colleagues).2
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Figure 1. A chest X-Ray, an anteroposterior view in deep inspiration, showing well defined, smoothly outlined, oval shaped soft tissue, opaque in density occupying the lower two-thirds of each lung.
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An ultrasonography of the chest revealed a large well-defined cyst with homogenous walls in both lungs posteriorly. There was no solid component, septae, or daughter cyst identified within each cyst. These findings were more in favor of congenital benign cysts rather than hydatid cysts. The ultrasonography of the abdomen and pelvis was normal. A computed tomography scan of the chest showed two large, bilateral, well circumscribed loculated cysts with chewing margins, the right measuring 116 x 91 mm and the left measuring 110 x 90 mm, both involving whole lungs in posterior lower zones with little remaining lung tissue (Figure 2). No calcification was seen within each cyst. The patient’s serum immunoglobulin titers were negative for Echinococcus Granulosus (< 1:16).
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Figure 2. A computed tomography scan of the chest showing two large bilateral, well circumscribed loculated cysts involving whole lungs in posterior lower zones with little remaining lung tissue.
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Due to the compressive atelectasis caused by these cysts and due to their individual nature, it was decided to expose these cysts surgically. The patient underwent bilateral posterolateral thoracotomies under general anaesthesia. Intraoperatively both cysts were found to be hydatid cysts which were first aspirated and then injected with hypertonic saline. This was followed by deroofing and a removal of all daughter cysts. There was no spillage of contents. The pleural cavities were thoroughly irrigated with hypertonic saline and the air leaks were sealed with 8 sutures using 4-0 prolene. Three chest tubes were placed bilaterally and the chest was closed primarily. The histopathological features of the sections from right and left lung cysts revealed cyst walls composed of amorphous densely staining laminated chitinous material. Numerous brood capsules were also seen. These features were consistent with hydatid cysts. Fluid culture was negative for pus cells and microorganisms. She was discharged three days later. To reduce a recurrence in the post operative period, she was given albendazole to be taken for 4 months.5 Her postoperative recovery was smooth with no evidence of sepsis, pneumonia or bronchiectasis that are sometimes reported after conservative parenchyma saving lung procedures.2 A two-year follow-up of the patient showed a complete resolution of all her symptoms, normal ESR and well expanded lungs with no residual cysts visible on the chest X-Ray.
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DISSCUSION
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Hydatid disease is caused by a hexacanth larval form of a dog tapeworm Echinococcus Granulosus, which causes unilocular hydatid cyst, or by Echinococcus Multilocularis which causes multilocular or alveolar type of hydatid cyst. The liver is the most common site for cyst formation (60%), followed by the lungs (20%), kidneys (3%) and brain (1%).
In the case discussed above, the 12-year-old girl presented with a giant hydatid cyst in each lung with each cyst occupying two-thirds of the hemithorax, is a strikingly symmetrical picture consistent with congenital cysts of the lungs. Once a hydatid cyst infiltrates the lungs, it can either get perforated into the bronchiole with expectoration of the germinative layer and spontaneous obliteration of the residual cavity; or it can enlarge in size to form a giant hydatid cyst.2 The latter phenomenon is seen mostly in the younger age group (mean age 25 years but the majority of cases fall into the 11 to 20 years age group) because less tissue resistance and higher elasticity in young patients allow the cyst to grow to a giant size, whereas adequate compliance of an uninvolved lung allows sufficient ventilation to delay the onset of symptoms, thus enhancing cyst growth.2 The cyst in our patient was uncomplicated because the germinative membrane had not been penetrated.2
Congenital cystic lesions include bronchogenic cyst (extralobar); cystic adenomatoid malformations (CAM) and congenital lobar overinflation (CLO) (intralobar). The mean age of occurrence of first clinical symptoms is 8.8 years according to Evrard V and coworkers (1 day to 62 years).6 In our patient, the provisional diagnosis of intralobar congenital cyst was made because of the symmetrical presentation of the cysts, equivocal findings on the computed tomography scan, an ultrasonography and most importantly negative Echinococcus Granulosus titers. However, the index of suspicion was still high because hydatid cysts are endemic to the area where the patient came from.
The treatment of choice for intralobar congenital cyst (CAM and CLO) is lobectomy or segmentectomy.7 On the contrary, conservative parenchyma saving procedures is the best option for giant hydatid cysts and resection should be avoided unless the lobe is thoroughly destroyed.2
In conclusion, giant hydatid cyst of the lung can occur bilaterally and symmetrically and in an endemic area there should be a high index of suspicion for hydatid cyst disease despite negative titers and equivocal radiological findings. Conservative surgery should be performed in such a case to avoid unnecessary loss of pulmonary reserves in an otherwise young patient.
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REFERENCES
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- Burgos R, Varela A, Castedo E, Roda J, Montero CG, Serrano S, et al. Pulmonary hydatidosis: surgical treatment and follow-up of 240 cases. Eur J Cardiothorac Surg
1999;16:628–35.[Abstract/Free Full Text]
- Halezeroglu S, Celik M, Uysal A, Senol C, Keles M, Arman B. Giant hydatid cysts of the lung. J Thorac Cardiovasc Surg
1997;113:712–7.[Abstract/Free Full Text]
- Burgos L, Baquerizo A, Munoz W, de Aretxabala X, Solar C, Fonseca L. Experience in the surgical treatment of 331 patients with pulmonary hydatidosis. J Thorac Cardiovasc Surg
1991;102:427–30.[Abstract]
- Lamy AL, Cameron BH, LeBlanc JG, Culham JA, Blair GK, Taylor GP. Giant hydatid lung cysts in the Canadian northwest: outcome of conservative treatment in three children. J Pediatr Surg
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- Yalcinkaya I, Er M, Ozbay B, Ugras S. Surgical treatment of hydatid cyst of the lung: review of 30 cases. Eur Respir J
1999;13:441–4.[Abstract]
- Evrard V, Ceulemans J, Coosemans W, De Baere T, De Leyn P, Deneffe G, et al. Congenital parenchymatous malformations of the lung. World J Surg
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- Coran AG, Drongowski R. Congenital cystic disease of the tracheobronchial tree in infants and children. Experience with 44 consecutive cases. Arch Surg
1994;129:521–7.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
