An analysis of clinical features of pulmonary giant hydatid cyst in adult population
Bulent Kocer M.D.a, Gultekin Gulbahar M.D.a, 
, 
, Serdar Han M.D.b, Elif Durukan M.D.c, Koray Dural M.D.a and Unal Sakinci M.D.a
aNumune Teaching and Research Hospital, Division of Thoracic Surgery, Ankara, Turkey
bKirikkale University, Medical Faculty, Department of Thoracic Surgery, Kirikkale, Turkey
cGazi University, Faculty of Medicine, Department of Public Health, Ankara, Turkey
Received 17 August 2007;
Abstract
Background
We performed an analysis of giant hydatid cysts (GCHs) detected in the adult population by comparison with the features of other simple hydatid cysts (CHs) in the light of the relevant literature.
Methods
The records of 74 adult patients who were operated on in our clinic for pulmonary CHs between 2001 and 2005 were retrospectively evaluated. Cysts that were 10 cm or larger in diameter on any plane were considered GCHs. The cysts were classified into 2 groups as GCHs (group A) and other (group B). The groups were then compared for age, sex, symptom, cyst location, preoperative complications, surgical procedure performed, operative morbidity, and mortality.
Results
Of 74 patients, 10 (13.5%) were in group A and 64 were in group B. No differences were detected between the clinical presentation, gender distribution, surgical procedure performed, and postoperative morbidity and mortality rates of GCHs and other cysts in adults. In both groups, there were no significant differences between the rates of involvement of 2 lungs (P = .527). However, both groups had lower lobe involvement, more markedly in group A (81.8% and 45.5% respectively; P = .023). Two patients in group A (20%) and 18 patients in group B (28.1%) had complicated cysts.
Conclusions
The tendency of GCH to involve the lower lobe of the lung compared to smaller cysts suggests underlying mechanisms other than lung elasticity in the late onset of the symptoms parallel to cyst growth.
Keywords: Hydatid disease; Lung; Adult
Article Outline
Simple hydatid cyst (CH) is the most common parasitic disease of the lungs. The lungs are the second most frequently involved organ following the liver. Echinococcus granulosus and multilocularis constitute the etiology of the disease.1 As in some Mediterranean countries where the disease is endemic, it remains an important public health problem in our country, and is particularly common in the rural areas.[2] and [3] The incidence rate for Turkey ranges between 1/50,000 and ½,000, with approximately 2,200 new cases every year.3
Cysts with a large diameter are considered giant hydatid cysts (GCHs), with their particular clinical features. They are more common in the pediatric population because of the higher elasticity of the lungs in this age group, which permits cyst expansion.4 The current study compared the clinical features of GCHs in an adult population with those of the smaller cysts and evaluated the results in the light of the available literature.
Methods
The records of 74 patients (≥16 years of age) who had undergone surgery in our clinic between January 2001 and December 2005 for pulmonary hydatidosis were retrospectively evaluated. The preoperative 2-sided lung graphs and computed tomography scans of the thorax of all patients were assessed for the size, location, and complication of the cysts. Information on cyst diameter was obtained based on the comparisons of tomography and peroperative findings. Cysts with a diameter of 10 cm or larger on any plane were considered GCH. The patients were grouped as those with GCHs (group A) and those with cysts other than GCHs (group B). All patients were followed-up for any complications and recurrence in the postoperative first, third, sixth, and twelfth months. Age distribution, sex, symptoms, cyst locations, preoperative complications, surgical procedures performed, and operative morbidity and mortality of the 2 groups were statistically compared. Statistical analyses were done by chi-square test. P values of .05 or less of considered statistically significant.
Results
There were 10 patients (13.5%) in group A and 64 patients in group B. Group A consisted of 6 male and 4 female patients with a mean age of 35.90 ± 18.78 years (range 17–67 years) and group B consisted of 29 male and 35 female patients with a mean age of 37.96 ± 16.50 years (range 16–82 years). The 2 groups did not differ significantly with respect to age and sex (P = .718 and P = .502).
The most common symptom in both groups was coughing (Table 1).
The diagnoses of all the patients were established in the light of the findings obtained from direct graphs and computed tomography of the thorax (Figure 1). In addition, all the patients were evaluated through abdominal ultrasound and cranial tomography. Based on all the findings, all of the patients in group A and 56 patients in group B (87.5%) were preoperatively diagnosed as having CHs.
There were no significant differences between the 2 groups for lung involvement (P = .527). In 10 patients 11 cysts were detected and in 64 patients 88 cysts were detected. In 1 patient (10%) in group A and in 10 patients (15.6 %) in group B, multifocal involvement was noted. While there was no bilateral involvement in any of the patients in group A, it was observed in 7 patients (10.95) in group B (Table 2). However, the difference was not statistically significant (P = .210).
Lower lobe involvement was more marked in group A (81.8%) than in group B (45.5%) (P = .023). The most commonly involved segment was the posterior basal segment of the lower lobe (60.5 in group A and 29.55 in group B, Table 3 and Table 4).
Distribution of the cysts in group A according to their locations
| Right lung | Left lung | ||||
|---|---|---|---|---|---|
| Location | n | % | Location | n | % |
| Upper Lobe | 1 | 9.1 | Upper Lobe | 1 | 9.1 |
| Apical | 1 | 9.1 | Apicoposterior | — | — |
| Posterior | — | — | |||
| Anterior | — | — | Anterior | 1 | 9.1 |
| Middle Lobe | — | — | Lingula | ||
| Medial | — | — | Superior | — | — |
| Lateral | — | — | Inferior | — | — |
| Lower Lobe | 4 | 36.4 | Lower Lobe | 5 | 45.4 |
| Superior | 1 | 9.1 | Superior | 2 | 18.2 |
| Lateral basal | — | — | Lateral basal | — | — |
| Anterior basal | — | — | Anteromedial basal | — | — |
| Medial basal | — | — | |||
| Posterior basal | 3 | 27.3 | Posterior basal | 3 | 27.3 |
| Total | 5 | 45.5 | Total | 6 | 54.5 |
Distribution of the cysts in group B according to their locations
| Right lung | Left lung | ||||
|---|---|---|---|---|---|
| Location | n | % | Location | n | % |
| Upper Lobe | 18 | 20.5 | Upper Lobe | 19 | 21.6 |
| Apical | 6 | 6.8 | Apicoposterior | 16 | 18.2 |
| Posterior | 10 | 11.3 | |||
| Anterior | 2 | 2.3 | Anterior | 3 | 3.4 |
| Middle Lobe | 6 | 6.8 | Lingula | 3 | 3.4 |
| Medial | 2 | 2.3 | Superior | 2 | 2.3 |
| Lateral | 4 | 4.6 | Inferior | 1 | 1.1 |
| Lower Lobe | 22 | 25.0 | Lower Lobe | 20 | 22.8 |
| Superior | 4 | 4.6 | Superior | 4 | 4.6 |
| Lateral basal | 3 | 3.4 | Lateral basal | 2 | 2.3 |
| Anterior basal | 3 | 3.4 | Anteromedial basal | — | — |
| Medial basal | — | — | |||
| Posterior basal | 12 | 13.6 | Posterior basal | 14 | 15.9 |
| Total | 46 | 52.2 | Total | 42 | 47.8 |
One patient in group A and 5 patients in group B (7.8%) had coexisting liver involvement (P = .813).
Two patients in group A (20%) and 18 patients in group B (28.1%) had complicated CHs (P = .590). One complicated cyst in group A was suppurated, whereas the other was ruptured, and in group B, 5 cysts were suppurated and 13 were ruptured. Cystotomy and capitonnage were the most commonly performed operative methods in both groups (Figure 2 and Figure 3). While none of the patients in group A underwent resection, only 2 patients in group B underwent a wedge resection procedure (Table 5).
The drain removal times of the groups were 4.10 ± 2.50 days (range 3–11 days) and 3.57 ± 2.00 days (range 1–13 days), respectively (P = .450). Postoperative hospital follow-up times of the patients in both groups were 8.30 ± 3.65 (range 5–18 days) for group A and 7.92 ± 3.81 days (range 4–24 days) for group B (P = .770).
The morbidity rate of group A was 10% (in 1 patient) and for group B, 9.4% (in 6 patients). There was no difference between operative morbidity rates of the 2 groups (P = .949). The most common postoperative complication was prolonged air leak for both groups (in 1 and 4 patients, respectively). One of the patients in group A developed empyema associated with prolonged air leak. Another complication was wound infection in 2 patients in group B.
The mortality rate of group B was 1.6% with 1 patient who died due to sepsis during postoperative intensive care period after perforation of a cyst in the abdomen leading to peritonitis. There was no mortality in group A.
No recurrence was observed in group A, while the recurrence rate for group B was 3.2% with recurrence in 2 patients (P = .570).
Comments
CH is an endemic parasitic disease in areas where cattle and sheep are raised.5 Pulmonary involvement by the disease has been reported to be 10% to 40%.[1] and [6] The spongy constitution of lung tissue allows for growth of the cyst to larger sizes than do the other organs. Thus, larger cysts are more common in children and young people because the lung tissue in these age groups is more elastic.[4], [7] and [8] In many studies, any cyst larger than 10 cm in diameter on any plane has been labeled as GCH because of its particular clinical features.[4] and [7] In young GCH cases, the remaining healthy tissue of the lungs provides sufficient ventilation, while the cyst in adults becomes symptomatic before it is fully grown.4 Therefore, the mean age of GCH cases has been determined to be lower than the mean age of the cases with other types of cysts.[4] and [9] However, the incidence rate of GCH in adults is significantly high. In an earlier study, the incidence rate of GCH was 31%, whereas in the adult group, it was 22%.9 In our study, the incidence rate of GCH was 13.5% for the adult group with a mean age of 35.9 years.
CH may be seen in any age group. Nevertheless, it is more common in the third and fourth decades in men.1 In a study by Kanat et al, the incidence rate for pediatric age group was higher among male children, although no difference was determined between the incidence rates of adult males and females.9 In one study, the incidence rate of GCH was higher in adult females, whereas it was higher among adult males in another study.7 In our study, no difference was observed between the incidence rates of other cysts or GCH for male or female sex.
Despite producing various symptoms depending on their location and size, CHs are usually asymptomatic. The symptoms and findings of a GCH are not different from those of other cysts. Coughing is the most common complaint of symptomatic cases.1 In cases with cysts perforated into the bronchi, severe cough is accompanied by expectorated cystic fluid containing germinative membrane particles. On the other hand, when the cyst is perforated into the pleura, symptoms such as persistent cough, dyspnea, and cyanosis due to hydropneumothorax may develop.1 In perforated CH, there may be a reaction of extreme sensitivity. In our study, the most common complaint was coughing. However, in 13 of 14 patients with ruptured cysts, cystic fluid expectoration accompanied the cough. Similarly, nearly one third of the cases had hemoptysis, but none had massive hemoptysis. The rates of symptoms for the 2 groups were not significantly different.
Although some studies claim left lobe involvement to be more common,10 a number of studies have shown cysts in pulmonary hydatidosis to be more commonly located in the right and lower lobes.[1], [5], [11] and [12] In our study, no difference between the involvement rates of the 2 lobes was detected. In group A, 81.8% of the cysts and in group B, 47.8% were located in lower lobe. Posterior basal segment of the lower lobe was the most frequently involved segment in both groups. GCH was more markedly located in the lower lobe compared to the other cysts. This may be due to asymptomatic state of cysts located in the lower lobe until they grow to a larger size, which is suggestive of mechanisms other than lung elasticity underlying the etiology.
The rate of coexisting hepatic and pulmonary involvement has been as high as 36.5%, In many studies, it has been reported to be between 7% and 18%[5] and [10]; in a large series, however, hepatic and pulmonary involvement rates were less than 10%.13 Hepatic and pulmonary involvement rates of our patients were 10% in patients with GCH and 7.8% in patients with other cysts, which was compatible with the results of earlier studies.
The principal treatment for pulmonary CH is surgical.[1], [14], [15] and [16] Because they can lead to compression and be ruptured or complicated, they should be planned for surgical treatment upon diagnosis. The aim of surgery is complete removal of the cyst, suturing bronchial openings, and sterilization and closing of the resultant cavity. Operations preserving the parenchyma such as enucleation, cystotomy, pericystectomy, and capitonnage should be primary choices.[4] and [7] Among those, cystotomy along with capitonnage is the most commonly used and recommended procedure.[16] and [17] Capitonnage is the obliteration of the residual cavity after the removal of the germinative membrane and suturing of bronchial openings. Halezeroglu et al, in their series of 47 patients with GCH, applied surgical procedures preserving the parenchyma in all but 3 patients who required lobectomy.4 They reported recurrence in only 1 case. Similarly, in our clinic, cystotomy and capitonnage have been the surgical preferences in the treatment of CHs.
If cysts in the right lobe are accompanied by hepatic involvement, the cyst in the liver may be intervened through phrenotomy.18 Phrenotomy may be preferred since it can be performed on both GCH and other cysts in 1 session and with no need for an additional incision. Topçu et al have successfully performed this procedure on a patient with GCH in the right lobe accompanied by hepatic involvement.19 Right thoracophrenotomy performed in a single session has been reported to reduce hospitalization time, as well as morbidity rates.[15] and [19] In our study, right thoracotomy and concomitant frenotomy were performed on 5 such GCH patients in group B.
Postoperative morbidity rates of CH patients vary between 0% and 17%, and prolonged air leak is the most common complication.[2], [13], [15], [17], [19], [20] and [21] The morbidity rate for our study was 10% in GCH patients, while it was 9.4% for the patients with other cysts. However, the difference between the 2 groups was not statistically significant.
Conclusions
In this study, there were no differences in clinical presentation, gender distribution, surgical procedure performed, postoperative morbidity, and mortality rates of the adult GCHs compared with other CH patients. This suggests that the size of the cyst that becomes symptomatic in adulthood may not be a predisposing factor for postoperative morbidity.
References
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