Congenital cystic adenomatoid malformation associated with ipsilateral eventration of the diaphragm
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《美国医学杂志》
1 Department of Pediatric Surgery, Lady Hardinge Medical College and associated Kalawati Saran Children's Hospital, New Delhi, India
2 Department of Pathology, Lady Hardinge Medical College and associated Kalawati Saran Children's Hospital, New Delhi, India
Abstract
A two-month-old girl was operated for a left-sided eventration of the diaphragm. At surgery, a mass representing an extralobar pulmonary sequestration (EPS) was found inferior to the left lobe of the lung and was excised. Histopathological examination of the resected specimen showed presence of a type II congenital cystic adenomatoid malformation (CCAM) within it. A review of the relevant literature is presented.
Keywords: Extralobar pulmonary sequestration; Congenital cystic adenomatoid malformation; Eventration diaphragm; Diaphragmatic hernia
Pulmonary sequestration (PS) refers to a malformation of the lung, which usually receives blood supply from one or more anomalous systemic arteries; no bronchial communication with the normal tracheobronchial tree occurs.[1] Sequestration has an estimated incidence of 0.15 % to 1.7 % in the general population, and was first described by Rokitansky and Reltorzik in 1861. Pryce, in 1946, introduced the term "sequestration" to describe the synonyms accessory pulmonary lobe, pulmonary aberration, supernumary lung, nebenlunge, and Rokitansky lobe.[2] There are two forms of sequestration: intralobar and extralobar. Intralobar sequestrations (IPS) are incorporated within the normal surrounding lung, and extralobar sequestrations (EPS) are completely separated from the normal lung and have a separate pleural covering.[1]
Congenital cystic adenomatoid malformations of the lung (CCAM) are uncommon congenital cystic lung lesions that arise from excessive disorganized proliferation of tubular bronchial structures excluding the alveoli.[3] CCAM are believed to represent focal pulmonary dysplasia because skeletal muscle may be identified from within the cyst wall.[4] This report describes a rare case of an infant operated upon for eventration of the diaphragm who was found to have an EPS in the ipsilateral hemithorax. Histopathological examination revealed that a type II CCAM was present within the resected sequestration.
Case report
A two-month old girl, weighing 2.8 kg, was brought with complaints of respiratory distress, fever and poor feeding for the past 20 days. The child was febrile and tachypneic. Examination of the chest showed bilateral conducted sounds, rhonchi and occasional crepitations. There was diminished air-entry in the lower zone of the left side of the chest. A plain x-ray of the chest showed evidence of a large left-sided diaphragmatic hernia Figure1. The child was treated initially with parenteral antibiotics (augmentin and amikacin), intravenous fluids and bronchodilators. After stabilization of the child's condition, surgical repair of the diaphragmatic anomaly was performed via a left subcostal incision. There was a large eventration of the left dome of the diaphragm. Incision of the attenuated portion of the diaphragm, prior to its repair, revealed a firm reddish-brown mass 3.5 x 3.0 cm in size below the lower lobe of the left lung and separate from it Figure2. The mass was supplied by a large blood vessel that appeared to be arising from the thoracic aorta. There was no bronchial communication. The mass was excised and plication of the diaphragm performed. Subsequent recovery was uneventful. Histopathological examination of the excised mass showed the lung parenchyma to be composed of many normal-sized to dilated alveoli lined by flattened or low-cuboidal epithileum and containing blood and alveolar macrophages in the lumen. There were numerous cystic, glandular spaces lined by stratified columnar epithileum and having a fibromuscular wall that showed the focal presence of skeletal muscles Figure3. The histological appearance was characteristic of CCAM type II.[5]
Discussion
EPS occurs predominantly (3:1) in males and the age at diagnosis ranges from the newborn period to adulthood.[1] In as many as 90% of cases, EPS is found on the left side, and as in our patient, Savic et al[6] reported that in 77.4% of cases, the EPS was found between the lower lobe of the lung and the diaphragm. In 9.7% of cases, the EPS was situated in the infradiaphragmatic and abdominal regions.[6] Gross et al[7] reported 3 cases of EPS presenting as a suprarenal mass related to the crura of the diaphragm. The arterial supply is usually from the thoracic or abdominal aorta, and unlike IPS where, in 95% of cases, the venous drainage is into the pulmonary veins, the venous drainage of EPS is usually into the azygos veins although occasionally drainage into the intercostal, portal, esophageal or adrenal veins has been reported.[8],[9]
In contrast to IPS where associated anomalies are uncommon, multiple other anomalies occur in 40% cases of EPS and as in our patient, ipsilateral posterolateral diaphragmatic hernia or eventration may be seen in 30% of series.[10] Chest-wall deformities, pericardial defects, arteriovenous fistula, enteric duplication, and congenital heart disease are all associated with EPS.[1]
Embryologically, PS are considered to be a part of the congenital bronchopulmonary foregut malformation (CBPFM) spectrum of defects[11],[12] and may be associated with bronchogenic cysts, esophageal duplication cysts, esophageal diverticula and CCAM of the lung on the same or opposite sides of the chest, or within the sequestration[11],[13],[14] CBPFM probably share a common embryogenesis despite diverse morphology, and represent a spectrum of abnormalities caused by defective budding, differentiation and separation of the primitive foregut. EPS probably develops from an abnormal, separate outpouching or budding of the foregut or by separation of a segment of developing lung from the primitive tracheobronchial tree during early gestation (6th-8th week of gestation).[13],[14] It has been suggested that with involution of the connection between the EPS and the foregut, a segment of primitive bronchial epithileum may remain and develop into a bronchogenic cyst.[14] If attachment to the foregut fails to regress, the occasional presence of a communication with the esophagus or stomach can occur.[7],[8],[14] PS is also a part of the pulmonary malinosculation spectrum, which includes all congenital lung anomalies where there is an abnormal connection (malinosculation) of one or more of the four major components of lung tissue-namely, tracheobronchial airway, lung parenchyma, arterial supply, and venous drainage, which in various combinations make up the lesions of CBPFM.[15] The association of EPS with diaphragmatic hernia and CCAM type II also point to an early defect in embryogenesis, prior to the 6th week of gestation when the diaphragm normally fuses.[14] In addition to our patient, in around 19 previously reported cases since 1949, CCAM has been found within an EPS.[14],[16] Chandran et al[3] reported a case of CCAM in the lower lobe of a lung associated with a separate EPS in the ipsilateral hemithorax.
Unlike IPS, EPS is usually asymptomatic. Infection is rarely a problem as an EPS has its own pleural covering and there is no bronchial communication. As in our patient, EPS is usually resected when it is discovered during another operative procedure such as repair of a diaphragmatic hernia.[1] It may also be diagnosed as a posterior, inferior mediastinal mass during an imaging study when PS is not suspected.[1] PS and CCAM may also be diagnosed antenatally. Fifteen to 50% of CCAMs decrease in size significantly before birth.[17],[18] Sequestration antenatally is known to cause mediastinal deviation, often associated with hydramnios. A detailed fetal ultrasound with Doppler flow to diagnose systemic blood supply should be done, with special attention paid to documenting polyhydramnios or hydrops because these are poor prognostic factors with high risk of fetal morbidity.[12] For the neonate with a thoracic mass, which may have regressed in utero, postnatal evaluation should follow the sequence of chest X-ray, ultrasound with Doppler, followed by chest CT-scan with intravenous contrast or magnetic resonance imaging (MRI) scanning.[12] These studies should delineate the thoracic lesion, demonstrate any connection with the tracheobronchial tree, and most importantly evaluate the blood supply so that surgery can be performed in a planned manner.[7],[9],[12] It has been stated that asymptomatic neonates with non-cystic EPS may be followed up without resection.[1],[17] However, others believe that all CBPFMs should be resected even if asymptomatic, because of the risk of infection, hemorrhage or malignancy, especially rhabdomyosarcoma which has been reported in CCAM and other cystic lung lesions representing maldeveloped pulmonary tissue.[19] Although infrequent, a patent communication with the esophagus and stomach can result in severe pulmonary infection with dire consequences.[7]
Surgical excision is usually straightforward as in our case, although the surgeon should remain aware of the possibility of unusual vasculature and a patent gastrointestinal fistula during surgery.[8],[9]
References
1. deLorimier AA. Respiratory problems related to the airway and lung. In. O'Neill Jr, JA, Rowe MI, Grosfeld JL, Fonkalsrud EW, Coran AG eds. Pediatric Surgery 5th edn., St. Louis Missouri; Mosby Year-Book Inc., Chap 57, 1998; 873-888.
2. Pryce DM. Lower lobe accessory pulmonary artery with intralobar sequestration of lung: Report of 7 cases. J Pathol 1946; 58: 457-467.
3. Chandran H, Upadhayay V, Pease PWB. Congenital cystic adenomatoid malformation and extralobar sequestration occurring independently in the ipsilateral hemithorax. Pediatr Surg Int 2000; 16 : 102-103.
4. Wang NS, Chen MF, Chen FF. The Glandular Component in Congenital Cystic Adenomatoid Malformation of the Lung. Respirology 1999; 4: 147-153.
5. Stocker JT, Madewell JE, Drake RM. Congenital cystic adenomatoid malformation of the lung. Classification and morphologic spectrum. Hum Pathol 1977; 8 : 155-171.
6. Savic B, Birtel FJ, Tholen W et al. Lung sequestration: report of seven cases and review of 540 published cases. Thorax 1979; 34: 96-101.
7. Gross E, Chen MK, Lobe TE, Nuchtern JG, Rao BN. Infradiaphragmatic extralobar pulmonary sequestration masquerading as an intra-abdominal suprarenal mass. Pediatr Surg Int 1977; 12: 529-531.
8. Sade RM, Clouse M, Ellis, Jr FH. The spectrum of pulmonary sequestration. Ann Thorac Surg 1974; 18: 644-658.
9. Vegunta RK, Teich S. Preoperative diagnosis of extralobar pulmonary sequestration with unusual vasculature: a case report. J Pediatr Surg 1999; 34: 1307-1308.
10. Carter R. Pulmonary sequestration. Ann Thorac Surg 1969; 7: 68-88.
11. Heithoff KB, Sane SM, Williams HJ et al. Bronchopulmonary foregut malformations. A unifying etiological concept. Am J Roentgenol 1976; 126 : 46-55.
12. Bratu I, Flageole H, Chen MF, Di Lorenzo M, Yazbeck S, Laberge JM. The multiple facets of pulmonary sequestration. J Pediatr Surg 2001; 36 : 784-790.
13. Luck SR, Reynolds M, Raffensperger JG. Congenital bronchopulmonary malformations. Curr Probl Surg 1986; 23: 247-314.
14. Stocker JT, Kagan-Hallet K. Extralobar pulmonary sequestration: analysis of 15 cases. Am Coll Clin Pathol 1979; 72 : 917-925.
15. Clements BS, Warner JO. Pulmonary sequestration and related congenital bronchopulmonary-vascular malformations: nomenclature and classification based on anatomical and embryological considerations. Thorax 1987; 42 : 401-408.
16. Conran RM, Stocker JT. Extralobar sequestration with frequently associated congenital cystic adenomatoid malformation, type 2: Report of 50 cases. Pediatr Dev Pathol 1999; 2: 454-463.
17. Adzick NS, Harrison MR, Crombleholme TM et al. Fetal lung lesions: Management and outcome. Am J Obstet Gynecol 1998; 179: 884-889.
18. Morin L, Crombleholme TM, D'Alton ME. Prenatal diagnosis and management of fetal thoracic lesions. Semin Perinatol 1994; 18 : 228-253.
19. Murphy JJ, Blair GK, Fraser GC et al. Rhabdomyosarcoma of the lung arising with congenital pulmonary cysts: Report of three cases. J Pediatr Surg 1992; 27: 3164-3167.(Chadha Rajiv, Singh Dharm)
2 Department of Pathology, Lady Hardinge Medical College and associated Kalawati Saran Children's Hospital, New Delhi, India
Abstract
A two-month-old girl was operated for a left-sided eventration of the diaphragm. At surgery, a mass representing an extralobar pulmonary sequestration (EPS) was found inferior to the left lobe of the lung and was excised. Histopathological examination of the resected specimen showed presence of a type II congenital cystic adenomatoid malformation (CCAM) within it. A review of the relevant literature is presented.
Keywords: Extralobar pulmonary sequestration; Congenital cystic adenomatoid malformation; Eventration diaphragm; Diaphragmatic hernia
Pulmonary sequestration (PS) refers to a malformation of the lung, which usually receives blood supply from one or more anomalous systemic arteries; no bronchial communication with the normal tracheobronchial tree occurs.[1] Sequestration has an estimated incidence of 0.15 % to 1.7 % in the general population, and was first described by Rokitansky and Reltorzik in 1861. Pryce, in 1946, introduced the term "sequestration" to describe the synonyms accessory pulmonary lobe, pulmonary aberration, supernumary lung, nebenlunge, and Rokitansky lobe.[2] There are two forms of sequestration: intralobar and extralobar. Intralobar sequestrations (IPS) are incorporated within the normal surrounding lung, and extralobar sequestrations (EPS) are completely separated from the normal lung and have a separate pleural covering.[1]
Congenital cystic adenomatoid malformations of the lung (CCAM) are uncommon congenital cystic lung lesions that arise from excessive disorganized proliferation of tubular bronchial structures excluding the alveoli.[3] CCAM are believed to represent focal pulmonary dysplasia because skeletal muscle may be identified from within the cyst wall.[4] This report describes a rare case of an infant operated upon for eventration of the diaphragm who was found to have an EPS in the ipsilateral hemithorax. Histopathological examination revealed that a type II CCAM was present within the resected sequestration.
Case report
A two-month old girl, weighing 2.8 kg, was brought with complaints of respiratory distress, fever and poor feeding for the past 20 days. The child was febrile and tachypneic. Examination of the chest showed bilateral conducted sounds, rhonchi and occasional crepitations. There was diminished air-entry in the lower zone of the left side of the chest. A plain x-ray of the chest showed evidence of a large left-sided diaphragmatic hernia Figure1. The child was treated initially with parenteral antibiotics (augmentin and amikacin), intravenous fluids and bronchodilators. After stabilization of the child's condition, surgical repair of the diaphragmatic anomaly was performed via a left subcostal incision. There was a large eventration of the left dome of the diaphragm. Incision of the attenuated portion of the diaphragm, prior to its repair, revealed a firm reddish-brown mass 3.5 x 3.0 cm in size below the lower lobe of the left lung and separate from it Figure2. The mass was supplied by a large blood vessel that appeared to be arising from the thoracic aorta. There was no bronchial communication. The mass was excised and plication of the diaphragm performed. Subsequent recovery was uneventful. Histopathological examination of the excised mass showed the lung parenchyma to be composed of many normal-sized to dilated alveoli lined by flattened or low-cuboidal epithileum and containing blood and alveolar macrophages in the lumen. There were numerous cystic, glandular spaces lined by stratified columnar epithileum and having a fibromuscular wall that showed the focal presence of skeletal muscles Figure3. The histological appearance was characteristic of CCAM type II.[5]
Discussion
EPS occurs predominantly (3:1) in males and the age at diagnosis ranges from the newborn period to adulthood.[1] In as many as 90% of cases, EPS is found on the left side, and as in our patient, Savic et al[6] reported that in 77.4% of cases, the EPS was found between the lower lobe of the lung and the diaphragm. In 9.7% of cases, the EPS was situated in the infradiaphragmatic and abdominal regions.[6] Gross et al[7] reported 3 cases of EPS presenting as a suprarenal mass related to the crura of the diaphragm. The arterial supply is usually from the thoracic or abdominal aorta, and unlike IPS where, in 95% of cases, the venous drainage is into the pulmonary veins, the venous drainage of EPS is usually into the azygos veins although occasionally drainage into the intercostal, portal, esophageal or adrenal veins has been reported.[8],[9]
In contrast to IPS where associated anomalies are uncommon, multiple other anomalies occur in 40% cases of EPS and as in our patient, ipsilateral posterolateral diaphragmatic hernia or eventration may be seen in 30% of series.[10] Chest-wall deformities, pericardial defects, arteriovenous fistula, enteric duplication, and congenital heart disease are all associated with EPS.[1]
Embryologically, PS are considered to be a part of the congenital bronchopulmonary foregut malformation (CBPFM) spectrum of defects[11],[12] and may be associated with bronchogenic cysts, esophageal duplication cysts, esophageal diverticula and CCAM of the lung on the same or opposite sides of the chest, or within the sequestration[11],[13],[14] CBPFM probably share a common embryogenesis despite diverse morphology, and represent a spectrum of abnormalities caused by defective budding, differentiation and separation of the primitive foregut. EPS probably develops from an abnormal, separate outpouching or budding of the foregut or by separation of a segment of developing lung from the primitive tracheobronchial tree during early gestation (6th-8th week of gestation).[13],[14] It has been suggested that with involution of the connection between the EPS and the foregut, a segment of primitive bronchial epithileum may remain and develop into a bronchogenic cyst.[14] If attachment to the foregut fails to regress, the occasional presence of a communication with the esophagus or stomach can occur.[7],[8],[14] PS is also a part of the pulmonary malinosculation spectrum, which includes all congenital lung anomalies where there is an abnormal connection (malinosculation) of one or more of the four major components of lung tissue-namely, tracheobronchial airway, lung parenchyma, arterial supply, and venous drainage, which in various combinations make up the lesions of CBPFM.[15] The association of EPS with diaphragmatic hernia and CCAM type II also point to an early defect in embryogenesis, prior to the 6th week of gestation when the diaphragm normally fuses.[14] In addition to our patient, in around 19 previously reported cases since 1949, CCAM has been found within an EPS.[14],[16] Chandran et al[3] reported a case of CCAM in the lower lobe of a lung associated with a separate EPS in the ipsilateral hemithorax.
Unlike IPS, EPS is usually asymptomatic. Infection is rarely a problem as an EPS has its own pleural covering and there is no bronchial communication. As in our patient, EPS is usually resected when it is discovered during another operative procedure such as repair of a diaphragmatic hernia.[1] It may also be diagnosed as a posterior, inferior mediastinal mass during an imaging study when PS is not suspected.[1] PS and CCAM may also be diagnosed antenatally. Fifteen to 50% of CCAMs decrease in size significantly before birth.[17],[18] Sequestration antenatally is known to cause mediastinal deviation, often associated with hydramnios. A detailed fetal ultrasound with Doppler flow to diagnose systemic blood supply should be done, with special attention paid to documenting polyhydramnios or hydrops because these are poor prognostic factors with high risk of fetal morbidity.[12] For the neonate with a thoracic mass, which may have regressed in utero, postnatal evaluation should follow the sequence of chest X-ray, ultrasound with Doppler, followed by chest CT-scan with intravenous contrast or magnetic resonance imaging (MRI) scanning.[12] These studies should delineate the thoracic lesion, demonstrate any connection with the tracheobronchial tree, and most importantly evaluate the blood supply so that surgery can be performed in a planned manner.[7],[9],[12] It has been stated that asymptomatic neonates with non-cystic EPS may be followed up without resection.[1],[17] However, others believe that all CBPFMs should be resected even if asymptomatic, because of the risk of infection, hemorrhage or malignancy, especially rhabdomyosarcoma which has been reported in CCAM and other cystic lung lesions representing maldeveloped pulmonary tissue.[19] Although infrequent, a patent communication with the esophagus and stomach can result in severe pulmonary infection with dire consequences.[7]
Surgical excision is usually straightforward as in our case, although the surgeon should remain aware of the possibility of unusual vasculature and a patent gastrointestinal fistula during surgery.[8],[9]
References
1. deLorimier AA. Respiratory problems related to the airway and lung. In. O'Neill Jr, JA, Rowe MI, Grosfeld JL, Fonkalsrud EW, Coran AG eds. Pediatric Surgery 5th edn., St. Louis Missouri; Mosby Year-Book Inc., Chap 57, 1998; 873-888.
2. Pryce DM. Lower lobe accessory pulmonary artery with intralobar sequestration of lung: Report of 7 cases. J Pathol 1946; 58: 457-467.
3. Chandran H, Upadhayay V, Pease PWB. Congenital cystic adenomatoid malformation and extralobar sequestration occurring independently in the ipsilateral hemithorax. Pediatr Surg Int 2000; 16 : 102-103.
4. Wang NS, Chen MF, Chen FF. The Glandular Component in Congenital Cystic Adenomatoid Malformation of the Lung. Respirology 1999; 4: 147-153.
5. Stocker JT, Madewell JE, Drake RM. Congenital cystic adenomatoid malformation of the lung. Classification and morphologic spectrum. Hum Pathol 1977; 8 : 155-171.
6. Savic B, Birtel FJ, Tholen W et al. Lung sequestration: report of seven cases and review of 540 published cases. Thorax 1979; 34: 96-101.
7. Gross E, Chen MK, Lobe TE, Nuchtern JG, Rao BN. Infradiaphragmatic extralobar pulmonary sequestration masquerading as an intra-abdominal suprarenal mass. Pediatr Surg Int 1977; 12: 529-531.
8. Sade RM, Clouse M, Ellis, Jr FH. The spectrum of pulmonary sequestration. Ann Thorac Surg 1974; 18: 644-658.
9. Vegunta RK, Teich S. Preoperative diagnosis of extralobar pulmonary sequestration with unusual vasculature: a case report. J Pediatr Surg 1999; 34: 1307-1308.
10. Carter R. Pulmonary sequestration. Ann Thorac Surg 1969; 7: 68-88.
11. Heithoff KB, Sane SM, Williams HJ et al. Bronchopulmonary foregut malformations. A unifying etiological concept. Am J Roentgenol 1976; 126 : 46-55.
12. Bratu I, Flageole H, Chen MF, Di Lorenzo M, Yazbeck S, Laberge JM. The multiple facets of pulmonary sequestration. J Pediatr Surg 2001; 36 : 784-790.
13. Luck SR, Reynolds M, Raffensperger JG. Congenital bronchopulmonary malformations. Curr Probl Surg 1986; 23: 247-314.
14. Stocker JT, Kagan-Hallet K. Extralobar pulmonary sequestration: analysis of 15 cases. Am Coll Clin Pathol 1979; 72 : 917-925.
15. Clements BS, Warner JO. Pulmonary sequestration and related congenital bronchopulmonary-vascular malformations: nomenclature and classification based on anatomical and embryological considerations. Thorax 1987; 42 : 401-408.
16. Conran RM, Stocker JT. Extralobar sequestration with frequently associated congenital cystic adenomatoid malformation, type 2: Report of 50 cases. Pediatr Dev Pathol 1999; 2: 454-463.
17. Adzick NS, Harrison MR, Crombleholme TM et al. Fetal lung lesions: Management and outcome. Am J Obstet Gynecol 1998; 179: 884-889.
18. Morin L, Crombleholme TM, D'Alton ME. Prenatal diagnosis and management of fetal thoracic lesions. Semin Perinatol 1994; 18 : 228-253.
19. Murphy JJ, Blair GK, Fraser GC et al. Rhabdomyosarcoma of the lung arising with congenital pulmonary cysts: Report of three cases. J Pediatr Surg 1992; 27: 3164-3167.(Chadha Rajiv, Singh Dharm)