Ann Thorac Surg 2008;86:249-253. doi:10.1016/j.athoracsur.2008.01.036
© 2008 The Society of Thoracic Surgeons
Original Articles: General Thoracic
Treatment of Congenital Cystic Adenomatoid Malformation: Should Lobectomy Always Be Performed?
Hong Kwan Kim, MDa,
Yong Soo Choi, MDa,
Kwhanmien Kim, MDa,
Young Mog Shim, MDa,
Gwan Woo Ku, MDa,
Kang-Mo Ahn, MDb,
Sang Il Lee, MDb,
Jhingook Kim, MDa,*
a Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
b Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
Accepted for publication January 14, 2008.
* Address correspondence to Dr Jhingook Kim, Department of Thoracic Surgery, Samsung Medical Center, 50 Ilwon-dong, Gangnam-gu, Seoul, 135-710, Korea (Email: jkimsmc{at}skku.edu).
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Abstract
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Background: Although parenchyma-saving resection makes it possible to preserve the lung parenchyma, most surgeons are reluctant to perform it for congenital cystic adenomatoid malformation (CCAM) because it could also result in recurrent pulmonary infection or residual lesion. This study compared the early and late postoperative outcomes according to the extent of resection in CCAM patients to determine if the extent of resection would influence the short- and long-term results.
Methods: Between 1995 and 2006, 45 patients underwent surgical resection for CCAM. Ten patients received a segmentectomy and 2 a wedge resection (the parenchyma-saving group), and 32 received a lobectomy and 1 a pneumonectomy (the lobectomy group). A retrospective analysis was done to compare the early and late postoperative outcomes between two groups.
Results: No significant differences were observed for severity and duration of preoperative symptoms. No in-hospital or late deaths occurred. There were no significant differences in the incidence of early postoperative complications and late morbidities between the two groups. No significant differences were observed between the two groups for hospital length of stay and duration of chest tube placement.
Conclusions: The early and late outcomes were excellent even after parenchyma-saving resection in patients with CCAM. We suggest that parenchyma-saving resection can be safely performed in selected patients with a well-confined CCAM lesion and thereby avoiding pneumonectomy in children.
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Introduction
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Congenital cystic adenomatoid malformation (CCAM) of the lung is a rare congenital abnormality [1]. Because patients with CCAM are susceptible to recurrent pulmonary infection if they are left untreated, surgical resection is the treatment of choice, and lobectomy is considered a standard procedure [2–5]. However, when more than one lobe is affected in CCAM patients, then extensive resection such as pneumonectomy or bilobectomy would be inevitable if lobectomy was attempted in every case. Likewise, when multiple lobes are involved in CCAM patients, lobectomy combined with either segmentectomy or wedge resection makes it possible to avoid a pneumonectomy. Furthermore, considering that CCAM is usually diagnosed in neonates and infants who have growth potential, parenchyma-saving resection would be ideal as long as it is feasible and safe.
Patients undergoing this parenchyma-saving resection, however, are likely to have early postoperative morbidities such as recurrent pulmonary infection or prolonged air leakage, and in cases with a residual lesion, malignant transformation as well as recurrent infection could occur during follow-up. For this reason, most surgeons have been reluctant to perform parenchyma-saving resection for CCAM and the optimal extent of resection in CCAM patients has been controversial [6, 7]. Despite these debates, we have attempted to preserve the lung parenchyma, when this is both feasible and safe, in selected patients with extensive lesions at our institution. The objectives of this study were to compare the early and late postoperative outcomes according to the extent of resection in CCAM patients and to determine if the extent of resection would influence the short- and long-term results.
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Patients and Methods
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Between January 1995 and December 2006, 45 consecutive patients with the diagnosis of CCAM underwent surgical resection at our institution. Their medical records were retrospectively reviewed to compare the clinical characteristics and the early and late postoperative results between the patients undergoing lobectomy and those undergoing parenchyma-saving resection, which was defined as the resection with an extent that is less than that of a lobectomy. Also considered to be parenchyma-saving resection was a segmentectomy of one lobe performed in conjunction with a lobectomy of another lobe to avoid a pneumonectomy, as well as multiple segmentectomies. The study was reviewed and approved by the Institutional Review Board of Samsung Medical Center.
Six patients (13.3%) were diagnosed with CCAM prenatally by fetal ultrasonography and their median age at the time of operation was 1.2 years. All patients underwent computed tomographic (CT) scanning of the chest to evaluate the extent of their CCAM. Surgical resection for CCAM was recommended when patients had symptoms such as respiratory difficulty or recurrent pulmonary infection. Even in asymptomatic patients, surgical resection was also indicated when the extent of lesion was estimated to involve more than half of a lobe, as seen on their CT scans. When patients were diagnosed prenatally or during the neonatal period, whether to proceed with surgical resection depended on the presence of symptoms; operations were postponed until the age of 6 months if patients showed no symptoms, but were urgently performed, regardless of the age at presentation, if patients showed significant symptoms.
A lobectomy was the procedure of choice for the treatment of CCAM. A segmentectomy or wedge resection was chosen when this was considered feasible owing to the well-confined pathology. When more than one lobe was affected, then a segmentectomy of one lobe combined with a lobectomy of another lobe or multiple segmentectomies were performed to avoid a pneumonectomy. A lobectomy was performed in 32 patients and a pneumonectomy was performed in 1; a segmentectomy was performed in 10 patients and wedge resection was performed in 2. Among the 10 patients who underwent a segmentectomy, a single segmentectomy was performed in 6 patients, multiple segmentectomies were done in 3, and a lobectomy of one lobe in conjunction with a segmentectomy of another lobe was done in 1. The operative techniques are summarized in Table 1. The study population was divided into two groups by the extent of resection; that is, 33 patients were in the lobectomy group (lobectomy or pneumonectomy), and 12 were in the parenchyma-saving group (segmentectomy or wedge resection).
A histopathologic examination was performed on all specimens and was reviewed by a pathologist. The lesions were histologically classified using the criteria suggested by Stocker: type I (macrocystic, multiple large cysts); type II (polymicrocystic, variable numbers of small cysts); type III (homogeneous echogenic mass). Twenty patients had type I CCAM, 24 had type II, and 1 had mixed type I and II. No patients had type III.
All patients were regularly followed up postoperatively. Telephone interviews were conducted with patients who were lost to follow-up to obtain the late postoperative outcomes. Descriptive statistics were used to describe patient characteristics and outcomes. The normally distributed continuous data were expressed as means ± standard deviations. Categoric data were expressed as counts and proportions. Student t tests and 
2 or Fisher exact tests were used to compare the continuous and categoric variables, respectively. Significance was accepted at values of p < 0.05.
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Results
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Patient Profile
The clinical characteristics of the study population are presented in Table 2. Twelve patients (26.7%) underwent a parenchyma-saving resection. The lobectomy group consisted of 22 boys and 11 girls (mean age, 13.7 ± 14.6 years). The parenchyma-saving group consisted of 7 boys and 5 girls (mean age, 4.3 ± 4.5 years). Before their operations, 21 patients (63.6%) in the lobectomy group and 8 (66.6%) in the parenchyma-saving group had symptoms such as pneumonia. The median duration of preoperative symptoms was 4.0 months for the patients who underwent a lobectomy compared with 2.0 months for those who underwent a parenchyma-saving resection. Five patients in the lobectomy group showed a lung abscess that was related to CCAM, but no patients in the parenchyma-saving group showed a lung abscess. No significant differences were observed between the lobectomy group and the parenchyma-saving group for severity of symptoms, the preoperative duration of symptoms, or the complications related to CCAM.
Early Postoperative Outcomes
There were no in-hospital deaths. Among the 33 patients who underwent a lobectomy or pneumonectomy for CCAM, 2 (6.1%) had early postoperative complications, including wound infection in 1 and a prolonged air leak in 1. Except for a patient who had a prolonged air leak postoperatively, none of the patients who underwent parenchyma-saving resection experienced early postoperative morbidities. The incidence of early postoperative complications in the two groups was not significantly different. The mean hospital length of stay was 7.6 ± 4.3 days in the lobectomy group and 7.8 ± 4.0 days in the parenchyma-saving group (p = 0.903). The mean duration of postoperative chest tube placement was 4.9 ± 1.9 days in the lobectomy group and 5.3 ± 3.7 days in parenchyma-saving group (p = 0.784).
Late Follow-Up Outcomes
Follow-up was completed for all the patients, with a mean duration of 63.8 months (range, 9.5 to 149.3 months). There were no significant differences in the follow-up duration between the two groups. No late deaths occurred during follow-up.
In the lobectomy group, two patients (6.1%) had late morbidities: 1 patient had spontaneous pneumothorax and mycoplasma pneumonia developed in 1 patient at 10 months after lobectomy; this patient recovered after antibiotic treatment. Among the parenchyma-saving group, only one late complication (8.3%) occurred during follow-up. Bacterial pneumonia developed 5 months postoperatively in the patient who had undergone multiple segmentectomies. There were no significant differences in the incidence of late morbidities between the two groups.
Eight patients (24.2%) in the lobectomy group and 8 (66.7%) in the parenchyma-saving group underwent postoperative CT scans during follow-up. No residual lesions were found in the lobectomy group, but 1 patient in the parenchyma-saving group showed a residual lesion. This patient had undergone a left lower lobe basal segmentectomy and he has been followed up for the residual lesion without any symptoms.
None of the patients who received operations during childhood reported growth retardation on their follow-up. The data for the early and late postoperative outcomes after surgical treatment for CCAM are summarized in Table 3.
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Comment
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Congenital cystic adenomatoid malformation is a rare congenital anomaly of the lung. Patients with CCAM usually present with respiratory difficulty, and recurrent pulmonary infection is often seen in neonates and infants [2, 8]. It is reasonable that surgical resection is considered the treatment of choice for patients with symptoms due to CCAM, but whether to perform surgical resection even for asymptomatic patients remains controversial [5, 9–12]. Many authors have agreed that early surgical resection should be performed before complications related to CCAM develop, whereas others have adopted a more conservative observational approach, suggesting that such risks might be insignificant compared with the morbidity that can occur after surgical resection [9–15]. Aziz and colleagues [11] revealed that only 10% of asymptomatic CCAM lesions developed complications when left untreated, and they suggested that a nonoperative approach might be a reasonable alternative for children with asymptomatic CCAM.
Most authors have nevertheless advocated early elective operation to avoid the potential risks of untreated CCAM such as recurrent pulmonary infection or malignant transformation [7, 9, 15–19]. The incidence of postoperative complications is also assumed to be lower after early elective operation for CCAM than after an urgent intervention for CCAM complications [5, 20]. Moreover, it has been known that resection of a compressive lung lesion enables the remaining lung to induce its compensatory growth [5]. To summarize, the accumulated hazards of pulmonary infection and the risks of malignancy later in life outweigh the risks of early and elective surgery [7]. It therefore stands to reason that we have performed urgent operations for CCAM patients when they have symptoms such as respiratory difficulty or recurrent pulmonary infection. In the same context, surgical resection was recommended even for the asymptomatic CCAM patients when the extent of the lesion was considered significant enough to result in complications related to CCAM.
Lobectomy is the procedure of choice for patients with CCAM, especially when the lesion is confined to a single lobe. Infants and children tolerate lobectomy well, with compensatory lung growth, so that the total lung volume and gas exchange capacity return toward normal during somatic maturation [12, 21]. However, when multiple lobes are affected in patients with CCAM, then extensive resection such as pneumonectomy or bilobectomy seems to be unavoidable if we stick to the principle of lobectomy. A parenchyma-saving procedure in these circumstances makes it possible to avoid performing extensive resection beyond a simple lobectomy procedure. Theoretically, as long as parenchyma-saving resection is feasible and safe, preserving the normal pulmonary parenchyma would be ideal in patients, such as neonates and infants, who have growth potential.
A more conservative policy of segmentectomy seems to have been followed by some investigators [17, 18]. Davenport and coworkers [7] advocated a conservative approach of performing lobectomy of the most involved lobe and performing segmentectomy of the remaining cysts when the lesion involved adjacent lobes in CCAM patients. Yet it should be noted that parenchyma-saving resection can be complicated by a prolonged air leak in the early postoperative period, and in patients with a residual lesion, malignant transformation as well as recurrent infection could develop during follow-up, which would necessitate a repeat operation [6, 18, 22]. For this reason, the optimal extent of resection in CCAM patients has been controversial.
Despite these potential disadvantages of parenchyma-saving resection, we have attempted to preserve the lung parenchyma whenever possible in selected cases. A segmentectomy or wedge resection was performed when it was considered feasible owing to the well-confined pathology. When more than one lobe was affected, then a segmentectomy in conjunction with lobectomy, or multiple segmentectomies, were performed to avoid pneumonectomy. In contrast with other researchers' previous concerns, our data showed excellent early and late outcomes. Of the 12 patients who underwent parenchyma-saving resection, only one incidence of a prolonged air leak occurred; during follow-up, only one patient was found to have a residual lesion, and this required no further treatment. The differences in the hospital length of stay or the duration of postoperative chest tube placement between the lobectomy group and the parenchyma-saving group were not significant.
In fact, it is difficult to explain the reason why the outcomes of parenchyma-saving resection were relatively good in our series. Possibly, we decided to preserve the pulmonary parenchyma in highly selected patients who had well-confined lesion and this might have led to our excellent results. This means, in other words, performing parenchyma-saving resection might not be desirable in patients with diffuse, poorly confined lesions, even though it is highly likely to perform a pneumonectomy in these cases due to multiple lobes involvement. Lobectomy is obviously the standard procedure for patients with CCAM, but parenchyma-saving resection should be taken into consideration for selected cases in which multiple lobes are involved and the procedure appears to be feasible due to the well-confined lesion.
Our study has several limitations. Because our data were retrospectively collected and parenchyma-saving resection was performed in only selected cases, it seems difficult to ascertain whether lobectomy should be always performed in CCAM patients. This might be inappropriate if we tried to determine which procedure would be optimal regarding the extent of resection in CCAM patients based solely on this series. Had we performed a prospective, randomized controlled trial, it would have been helpful to determine if parenchyma-saving resection could be justified even in patients with localized CCAM.
In addition, the study population was rather small and thus it does not seem that the power of our suggestions is so strong as to be conclusive. Despite these limitations, however, we can firmly suggest that parenchyma-saving resection is one of the surgical options in highly selected cases of CCAM, especially when multiple lobes are involved and so performing a pneumonectomy is inevitable.
In summary, although a lobectomy was the procedure of choice at our institution for the treatment of CCAM, parenchyma-saving resection was performed in selected patients to avoid an extensive resection. We compared the early and late postoperative outcomes according to the extent of resection in CCAM patients and we tried to determine if the extent of resection would influence both the short- and long-term results. The early and late outcomes were excellent even after parenchyma-saving resection, in contrast to the previous concerns raised by the past reports. We suggest that parenchyma-saving resection can be safely performed in selected patients with a well-confined CCAM lesion, and so this avoids performing pneumonectomy in children, a procedure with potentially devastating outcomes.
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Abstract
Introduction
