Congenital cystic adenomatoid malformation type III associated with congenital anomalies

Amaç

Konjenital anomalilerin eşlik ettiği akciğere ait konjenital kistik adenomatöz malformasyon tip III olgusu sunuldu.

Olgular

Karyotipi 46 XY olan ölü erkek bebek, gebeliğin 19. haftasındaki düşüğü takiben incelendi. Anne 22 yaşında olup eşi ile birinci dereceden akraba idi. Takipler sırasında fetusta asit ve spina bifida saptanmış ve kistik fibrozdan şüphe edilmişti. Otopside her iki akciğer sert ve büyük olup torasik basınca bağlı olarak kaburgaların izlerini taşımaktaydı. Kesitlerde birbirinden ayrı duran 0.1-0.2 mm çapında kistler mevcuttu. Mikroskopik incelemede, içinde bronşiole benzer yapılar bulunan gevşek bir mezankimal interstisyum ile birbirlerinden ayrılan, alçak kübik epitel ile döşeli alveol benzeri yapılar saptandı. Ayrıca bu yapıların çevresinde ne kıkırdak doku ve mukojen hücreler, ne de elastik doku ile düz veya çizgili kasa ait yapılara rastlandı.

Sonuç

Bu bulgularla olguya akciğerin konjenital kistik adenomatoid malformasyonu, Stocker tip III tanısı koyuldu.

Anahtar Kelimeler

Konjenital kistik adenomatoid malformasyon, Konjenital pulmoner traktus malformasyonu

Giriş

Congenital cystic adenomatoid malformation of the lung (CCAM) is a rare disorder mostly seen in newborn and stillborn infants. It is a developmental malformation of the lungs in which there is a defect in formation of terminal and respiratory bronchioles and alveolar ducts. Our case is a bilateral CCAM, type III associated with congenital anomalies. Because of the rarity of bilaterality in CCAM cases and association of congenital anomalies in CCAM type III, together with this case being the only one amongst our autopsies; we have found it worthwhile to report.

Olgular

Our case is a stillborn male fetus weighning 250 gr, at 19th week of gestation, delivered to a 22-year old white female prima gravid. Mother, married her 1st degree relative (her uncle's son), smoked 5 cigarettes a day. During her follow-up in a non-university hospital, two anomalies, lomber spinabifida and fetal ascites were observed in USG and pancreatic cystic fibrosis was suspected. Upon tissue culture karyotype 46XY was determined.
AUTOPSY FINDINGS
Gross autopsy examination revealed the following features: Macera male fetus with a slightly large head, low set ears with depression of the nasal root, fused eyelids with globes in proper position syndactyly, chin smaller than normal, distended abdomen due to ascites, lomber bifid spine and imperforation of the anus (Figure 1). In internal examination, grossly both of the lungs  were firm, bulky and showed depressions on the surfaces due to thoracic cage pressure (Figure 2). A few scattered small cysts 0.1-0.2 in mm diameter were observed both on the surface and the  cross section of the lungs. Also there was a hematoma within the heart chambers, and ascites in the
abdomen. No other abnormalities in internal or external organs were detected. Upon microscopic examination the malformation was seen to consist of alveolus-like structures lined by low cuboidal epithelium separated by loose
mesenchymal interstitial tissue and interspersed bronchiole-like structures (Figure 3A-3B). Cartilage and mucogenic cells were not detected No elastic tissue or smooth muscle were found around these structures. Also, no striated muscle were seen in the mesenchymal tissue. With these findings, our case demonstrates the pathological eatures of congenital cystic adenomatoid malformation of the lung, Stocker type III.

Tartışma

Previously, the term “congenital cystic disease of the lung” was used for a wide variety of cystic pulmonary abnormalities upon detection of radiolucencies in chest roentgenograms without pathologic confirmation. A study by Koontz showed that some cases of cystic fibrosis, postinflammatory pneumatocels and bronchiectasis as well as some sequestrations, hilar and bronchogenic cysts, and emphysematous lesions were reported as congenital cystic disease of the lung.
In 1949, separate entity, “congenital adenomatoid malformation of the lung” was designated by Chin and Tang. CCAM is a developmental malformation of terminal and respiratory bronchioles and alveolar ducts . Althoughs, CCAM is mainly a disorder of the newborn and stillborn infants, there have been 2 adult cases of CCAM reported in the literature (1, 4).
The lesions seen in CCAM are most of the time unilateral (confined to one lobe/ segment/ whole lung); bilateral lesions were very rarely detected. Here, in our case we have encountered bilateral lesions in the lungs.
CCAM is usually accompained with maternal polyhydramnions, hydrops fetalis and fetal ascites. Fetal ascites was present in the case we present.
On the other hand, congenital anomalies such as bilateral renal agenesis/dysgenesis, extralobar pulmonary sequestration, cardiovascular malformation, diaphragmatic hernia, jejunal atresia, pulmonary hypoplasia and skeletal malformations may be associated with this entity; most commonly in type II. Our case, CCAM type III, was also associated with congenital anomalies.
Recently, a new attempt has been made by Dr. Thomas Stocker, MD, to rename this entity as “Congenital pulmonary airway malformation”, for CCAM is a defect in differentiation of the tracheobronchial tree. According to Dr. Stocker, the classification of CCAM falls into 5 categories, which are:
A. CCAM Type O (CPAM): Acinar dysgenesis (agenesis)-Tracheobronchial origin.
B. CCAM Type 1 (CPAM 1): Large cyst type of bronchial/bronchiolar origin
C. CCAM Type 2 (CPAM 2): Intermediate cyst type of bronchiolar origin
D. CCAM Type 3 (CPAM): Small cyst type of bronchiolar/alveolar duct origin
CCAM Type 3 which almost exclusively occurs in males (as is the case we present), accounts for 8-10% of CCAM cases. In 79% of the cases it is associated with maternal polyhydramnios. This type of CCAM is the original congenital adenomatoid malformation of theğ lung described by Chin and Tang in 1949.
Grossly, harge bulky lesions involve the entire lobe or even an entire lung. In our case the lesions entirely involved both of the lungs.
Microscopically, lesions consist of randomly scattered bronchiolar/alveolar duct-like structures lined by low cuboidal epithelium, which are surrounded by alveoli lined by cuboidal epithelium (Figures 3A, 3B, 4A, 4B).
E. Type 4 (CPAM 4): Peripheral cyst type distal acinar origin.

Sonuç

In our 10-year series of autopsies we have had only a few CCAM case, with this case being the only one associated with congenital anomalies. Briefly, we present a case of bilateral CCAM type 3 associated with congenital anomalies, diagnosed in the 2nd trimester as a still fetus.

 

Kaynaklar

1. Gilber E, Barness EG: Respiratory system. Potter’s Pathology of the fetus and infants Ed. E. Gilbert, Ed, Bauness St ousie, Mosby, 1997; 741-6
2. Hutchin P, Friedman PJ, Saltzstein SL: Congenital cystic, adenomatoid malformation with anomalous blood supply. Thor Cardiovasc Surgj 1971; 62: 220-5
3. Bale PM: Congenital cystic malformation of lung. A form of congenital bronchiolar (adenomatoid) malformation. AJCP 1979; 71: 41-420
4. Askin FB: Respiratory tract disorders in the fetus and neonate. Textbook of fetal and perinatal pathology. Ed. J.S. Wigglessworth Ed. D.B. Singer 2. United states of America, Blackweel Science 1997; 567-71
5. Lauding BH, Dixon LQ: Congenital malformation and genetic disorders of the respiratory tract (larynx, trachea, bronchi and lungs). American Review of Respiratory Disease 1979; 120: 151-85
6. Stocker JT: The respiratory tract. Pediatric Pathology. Ed. JJ Stocker, Ed. LP Dehner. Philadelphia, J.B. Lippincott Company. 1991; 518-32
7. Stocker JT: XXII International Congress of the International Academy of Pathology and 13th world congress of Academic and Enviromental Pathology. October 18-23, 1998, Nice France. Symposium II 1998; 205-7
 

	Dosya / Açıklama
	Figure 1 Gross view of the fetus: stillborn male fetus at 19 week of gestation.External abronmalities: Slightly large head, low set ears, fusion of the eyelidis with globes properly placed, wide and depressed nasal root, chin smaller than normal, syndactyly, distended abdomen anus and maceration observed.
	Figure 2 Grossly both of the lungs are firm and bulky, showing depressions on the surface due to thoracic cage pressure. A few scattered small cysts 0,1-0.2 mm in diameter seen both on the surface and in the cross section of the lungs.
	Figure 3 a-b Fetal microscopic findings: Low-power view of the lung: A portion of the bronchus can be seen on the right and themultiple bronchiolar/alveolar duct like structures (resembling an immature lung) (HEX40).