An Autopsy Case of Congenital Pulmonary Lymphangiectasis Masquerading as Pulmonary Interstitial Emphysema

Congenital pulmonary lymphangiectasis (CPL) is a rare and poorly documented disease of neonates, and is characterized by prominent and diffuse microcystic lymphatic dilation in the septal, subpleural and peribronchial tissue throughout both lungs. Although an accurate incidence of CPL is elusive, a previous autopsy study has suggested that approximately 1% of all infants stillborn or dead in the neonatal period have CPL (Laurence KM, 1955), and at least 30 and 130 cases of CPL have been reported in Japan and in the world, respectively. According to previous CPL reports, males are affected more than females, and there is no familial predisposition in most cases. However, a few cases have described an association with genetic disorders, such as Noonan, Down, Turner, and Fryns syndromes (Fryns JP & Moerman P, 1993; Jacquemont S et al., 2000). CPL is generally divided into two groups: primary (congenital) and secondary. In addition, Noonan classified CPL into three groups (Noonan JA et al., 1970): group 1 is characterized by generalized lymphangiectasis (lymphedema with intestinal lymphangiectasis) (Bellini C et al., 2001; Maclean JE et al, 2002); in group 2, CPL is caused by pulmonary venous hypertention or obstruction associated with surgery, radiation, infection, tumor, or cardiovascular anomalies including anomalous pulmonary venous drainage or cor triatriatum (Gilewski MK et al., 1996; Verlaat CWM et al., 1994); group 3 is due to a primary developmental defect of the pulmonary lymphatics (Huber A et al., 1991; Moerman P et al., 1993). Therefore, groups 1 and 3 of CPL are primary (congenital), and group 2 is secondary. In particular, group 3 CPL is characterized by severely disturbed pulmonary gas exchange and a poor prognosis (Hoehn T et al., 2006), and some reports have shown that neonates with group 3 CPL have lymphatic dilation in the lungs and multiple other organs, and pursue an adverse clinical course (Frank J et al., 1955; Hirano H et al., 2004; Mckendry JBJ et al., 1957). Because of the clinicopathological similarities between group 3 CPL and pulmonary interstitial emphysema (PIE), CPL tends to be misdiagnosed as PIE (Finder J & Steinfeld J, 2004; Xiao ZY et al., 2009). Although a conclusive diagnosis of CPL can only be made pathologically or by autopsy, CPL should be distinguished from PIE because of their distinct treatments and prognoses (Laurence KM, 1955; Finder J & Steinfeld J, 2004; Xiao ZY et al., 2009).