Congenital cystic adenomatoid malformation
 Discussion of Congenital cystic adenomatoid malformation
- Congenital cystic adenomatoid malformation (CCAM) of the lung is an uncommon cause of respiratory distress in neonates and infants.
- CCAM is characterized by a multicystic mass of pulmonary tissue with an abnormal proliferation of bronchial structures.
- CCAM is classified into three histologic types.
- Type I is composed of variable-size cysts, with at least one dominant cyst (>2 cm in diameter). This is the most common (75%) form.
- Type II congenital cystic adenomatoid malformation is composed of smaller, more uniform cysts less than 1 cm in diameter (10% to 15% of all congenital cystic adenomatoid malformations).
- Type III congenital cystic adenomatoid malformation is a solid mass composed of bronchoalveolar microcysts.
- The natural history and prognosis of CCAM are variable, depending on the size rather than histologic type of the lesion.
- The differential diagnosis includes
- Among infants in whom the malformation is diagnosed postnatally, one-half to two-thirds will have some form of respiratory distress or compromise.
- The presentation in older patients is usually recurrent pulmonary infections.
- CCAM usually involves a single lobe, multilobar involvement being infrequent.
 Imaging Findings for Congenital cystic adenomatoid malformation
- The postnatal diagnosis is made with plain chest radiography, which demonstrates multiple air-filled thin-walled cysts that vary in size.
- Unlike in diaphragmatic hernia, the distribution of abdominal bowel gas is normal.
- CT can be useful for characterizing congenital cystic adenomatoid malformation by showing its location and extent, and for differentiating it from congenital lobar emphysema and bronchogenic cysts.
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 References for Congenital cystic adenomatoid malformation
- Teresa Berrocal, Carmen Madrid, Susana Novo, Julia Gutiérrez, Antonia Arjonilla, and Nieves Gómez-León. Congenital Anomalies of the Tracheobronchial Tree, Lung, and Mediastinum: Embryology, Radiology, and Pathology. RadioGraphics 2004 24: 17e.