Extralobar Sequestration with Frequently Associated Congenital Cystic Adenomatoid Malformation, Type 2: Report of 50 Cases

Abstract

Extralobar pulmonary sequestration (ELS) represents a mass of pulmonary parenchyma separate from the normal lung. The coexistence of congenital cystic adenomatoid malformation (CCAM) in ELS has been reported. To define this association, the clinical, gross, and histologic features of 50 ELS cases were analyzed. The age at diagnosis varied from birth to 65 years with 24% of cases diagnosed prenatally and 61% (23/38) diagnosed within the first 3 months of life. Fifty-two percent of cases were in females and 48% in males. Forty-eight percent of ELS(s) were located in the left hemithorax, 20% in the right hemithorax, 8% in the anterior mediastinum, 6% in the posterior mediastinum, and 18% beneath the diaphragm. The blood supply to the sequestration in 77% of cases was directly from the aorta. Grossly, the lung, though hypoplastic in some cases, was otherwise unremarkable. Fifty percent (23/46) of ELS cases were associated with a coexistent CCAM. In contrast to the series as a whole, 92% (11/12) of the ELS/CCAM cases, excluding those prenatally diagnosed, were diagnosed within the first 3 months and 57% occurred in females. ELS/CCAM lesions, while randomly distributed, were more frequently seen on the left side. Gross features of the ELS/CCAM cases were similar to those cases with ELS alone. All CCAM cases had a type 2 pattern on histologic examination with 48% of those cases also displaying rhabdomyomatous dysgenesis. Our findings indicate that the occurrence of CCAM in ELS is more frequent than reported in the literature and differs in presentation from ELS cases not associated with CCAM.

Late-Onset Congenital Cystic Adenomatoid Malformation of the Lung

“…Large alveolus-like structures are present between the cysts. In 50% of the cases, type II CCAM has been found to be associated with extralobar pulmonary sequestration [3]. Type III, accounting for 10%, forms a solid and bulky mass, composed of regularly spaced bronchiole-like structures separated by masses of alveolus-like structures lined by cuboidal epithelium.…”

“…It was first described as a distinct pathological entity in 1949 by Ch’in and Tang [1]and classified according to histological criteria by Stocker et al [2, 3]in 1977. Its etiology and pathogenesis remain unknown.…”

Rare localized extralobar sequestration with congenital cystic adenomatoid malformation: a case report

“…Pulmonary sequestration with CCAM has recently been reported more frequently in pediatric surgery [2–4]. Due to the presence of a mediastinal tumor with a cystic mass in the lung, a sequestration was also suspected in this patient.…”

“…Richard et al [2] reported that proportion of ELS with frequently associated congenital cystic adenomatoid malformation type II was approximately 50%. Recently, the pathogenesis of CCAM, LLS, ELS, and lobar emphysema has been thought to have common origins in different stages of lung development and at different sites and times, under the influence of airway obstruction [3, 4].…”

Congenital Pulmonary Malformation in Children

“…Smooth and striated muscle fibres are seen in types 1 and 2, respectively [4]. A coexistent CPAM type 2 has been reported in half of the patients with extralobar sequestration (ELS) [6], however the separation from the lung and the presence of a systemic blood supply are helpful to distinguish between these entities [3]. Type 4 lesions contain large cysts lined with flat alveolar cells, some of which contain surfactant [7].…”